diff --git a/__tests__/dataframe.test.ts b/__tests__/dataframe.test.ts
index 3972d3416..550b6d542 100644
--- a/__tests__/dataframe.test.ts
+++ b/__tests__/dataframe.test.ts
@@ -2249,7 +2249,6 @@ describe("meta", () => {
     expect(dfString).toStrictEqual(expected);
   });
 });
-
 test("Jupyter.display", () => {
   const df = pl.DataFrame({
     os: ["apple", "linux"],
@@ -2329,4 +2328,79 @@ describe("additional", () => {
     const actual = df.toRecords();
     expect(actual).toEqual(rows);
   });
+  test("upsample", () => {
+    const df = pl
+      .DataFrame({
+        date: [
+          new Date(2024, 1, 1),
+          new Date(2024, 3, 1),
+          new Date(2024, 4, 1),
+          new Date(2024, 5, 1),
+        ],
+        groups: ["A", "B", "A", "B"],
+        values: [0, 1, 2, 3],
+      })
+      .withColumn(pl.col("date").cast(pl.Date).alias("date"))
+      .sort("date");
+
+    let actual = df
+      .upsample("date", "1mo", "0ns", "groups", true)
+      .select(pl.col("*").forwardFill());
+
+    let expected = pl
+      .DataFrame({
+        date: [
+          new Date(2024, 1, 1),
+          new Date(2024, 2, 1),
+          new Date(2024, 3, 1),
+          new Date(2024, 4, 1),
+          new Date(2024, 3, 1),
+          new Date(2024, 4, 1),
+          new Date(2024, 5, 1),
+        ],
+        groups: ["A", "A", "A", "A", "B", "B", "B"],
+        values: [0.0, 0.0, 0.0, 2.0, 1.0, 1.0, 3.0],
+      })
+      .withColumn(pl.col("date").cast(pl.Date).alias("date"));
+
+    expect(actual).toFrameEqual(expected);
+
+    actual = df
+      .upsample({
+        timeColumn: "date",
+        every: "1mo",
+        offset: "0ns",
+        by: "groups",
+        maintainOrder: true,
+      })
+      .select(pl.col("*").forwardFill());
+
+    expect(actual).toFrameEqual(expected);
+
+    actual = df
+      .upsample({ timeColumn: "date", every: "1mo" })
+      .select(pl.col("*").forwardFill());
+
+    expected = pl
+      .DataFrame({
+        date: [
+          new Date(2024, 1, 1),
+          new Date(2024, 2, 1),
+          new Date(2024, 3, 1),
+          new Date(2024, 4, 1),
+          new Date(2024, 5, 1),
+        ],
+        groups: ["A", "A", "B", "A", "B"],
+        values: [0.0, 0.0, 1.0, 2.0, 3.0],
+      })
+      .withColumn(pl.col("date").cast(pl.Date).alias("date"));
+
+    expect(actual).toFrameEqual(expected);
+
+    actual = df
+      .upsample({ timeColumn: "date", every: "1m" })
+      .select(pl.col("*").forwardFill());
+
+    expect(actual.shape).toEqual({ height: 174_241, width: 3 });
+  });
 });
diff --git a/package.json b/package.json
index 3d106fd86..176cd8928 100644
--- a/package.json
+++ b/package.json
@@ -54,17 +54,17 @@
     "precommit": "yarn lint && yarn test"
   },
   "devDependencies": {
-    "@biomejs/biome": "^1.5.1",
-    "@napi-rs/cli": "^2.17.0",
+    "@biomejs/biome": "^1.5.3",
+    "@napi-rs/cli": "^2.18.0",
     "@types/chance": "^1.1.6",
-    "@types/jest": "^29.5.11",
-    "@types/node": "^20.10.8",
+    "@types/jest": "^29.5.12",
+    "@types/node": "^20.11.17",
     "chance": "^1.1.11",
     "jest": "^29.7.0",
     "source-map-support": "^0.5.21",
-    "ts-jest": "^29.1.1",
+    "ts-jest": "^29.1.2",
     "ts-node": "^10.9.2",
-    "typedoc": "^0.25.7",
+    "typedoc": "^0.25.8",
     "typescript": "5.3.3"
   },
   "packageManager": "yarn@4.0.2",
diff --git a/polars/dataframe.ts b/polars/dataframe.ts
index 0742d8398..fcd19702a 100644
--- a/polars/dataframe.ts
+++ b/polars/dataframe.ts
@@ -57,12 +57,12 @@ interface WriteMethods {
    * @param options.sep - Separate CSV fields with this symbol. _defaults to `,`_
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.writeCSV()
+   * ... });
+   * > df.writeCSV();
    * foo,bar,ham
    * 1,6,a
    * 2,7,b
@@ -81,7 +81,7 @@ interface WriteMethods {
    * ...     callback(null);
    * ...   }
    * ... });
-   * > df.head(1).writeCSV(writeStream, {hasHeader: false})
+   * > df.head(1).writeCSV(writeStream, {hasHeader: false});
    * writeStream: '1,6,a'
    * ```
    * @category IO
@@ -167,9 +167,9 @@ interface WriteMethods {
  * @example
  * Constructing a DataFrame from an object :
  * ```
- * > data = {'a': [1n, 2n], 'b': [3, 4]}
- * > df = pl.DataFrame(data)
- * > df
+ * > const data = {'a': [1n, 2n], 'b': [3, 4]};
+ * > const df = pl.DataFrame(data);
+ * > console.log(df.toString());
  * shape: (2, 2)
  * ╭─────┬─────╮
  * │ a   ┆ b   │
@@ -189,10 +189,9 @@ interface WriteMethods {
  * In order to specify dtypes for your columns, initialize the DataFrame with a list
  * of Series instead:
  * ```
- * > data = [pl.Series('col1', [1, 2], pl.Float32),
- * ...         pl.Series('col2', [3, 4], pl.Int64)]
- * > df2 = pl.DataFrame(series)
- * > df2
+ * > const data = [pl.Series('col1', [1, 2], pl.Float32), pl.Series('col2', [3, 4], pl.Int64)];
+ * > const df2 = pl.DataFrame(series);
+ * > console.log(df2.toString());
  * shape: (2, 2)
  * ╭──────┬──────╮
  * │ col1 ┆ col2 │
@@ -207,9 +206,9 @@ interface WriteMethods {
  *
  * Constructing a DataFrame from a list of lists, row orientation inferred:
  * ```
- * > data = [[1, 2, 3], [4, 5, 6]]
- * > df4 = pl.DataFrame(data, ['a', 'b', 'c'])
- * > df4
+ * > const data = [[1, 2, 3], [4, 5, 6]];
+ * > const df4 = pl.DataFrame(data, ['a', 'b', 'c']);
+ * > console.log(df4.toString());
  * shape: (2, 3)
  * ╭─────┬─────┬─────╮
  * │ a   ┆ b   ┆ c   │
@@ -250,12 +249,12 @@ export interface DataFrame
    * ___
    * Example
    * ```
-   * >  df = pl.DataFrame({
+   * >  const df = pl.DataFrame({
    * ...      'a': [1.0, 2.8, 3.0],
    * ...      'b': [4, 5, 6],
    * ...      "c": [True, False, True]
-   * ...      })
-   * ...  df.describe()
+   * ...      });
+   * ... df.describe()
    * shape: (5, 4)
    * ╭──────────┬───────┬─────┬──────╮
    * │ describe ┆ a     ┆ b   ┆ c    │
@@ -283,13 +282,13 @@ export interface DataFrame
    * @param name
    * @example
    * ```
-   * >  df = pl.DataFrame({
+   * >  const df = pl.DataFrame({
    * ...    "foo": [1, 2, 3],
    * ...    "bar": [6.0, 7.0, 8.0],
    * ...    "ham": ['a', 'b', 'c'],
    * ...    "apple": ['a', 'b', 'c']
-   * ...  })
-   * >  df.drop(['ham', 'apple'])
+   * ...  });
+   * >  console.log(df.drop(['ham', 'apple']).toString());
    * shape: (3, 2)
    * ╭─────┬─────╮
    * │ foo ┆ bar │
@@ -314,12 +313,12 @@ export interface DataFrame
    * ___
    * @example
    * ```
-   * >  df = pl.DataFrame({
+   * >  const df = pl.DataFrame({
    * ...    "foo": [1, 2, 3],
    * ...    "bar": [6, null, 8],
    * ...    "ham": ['a', 'b', 'c']
-   * ...  })
-   * >  df.dropNulls()
+   * ...  });
+   * > console.log(df.dropNulls().toString());
    * shape: (2, 3)
    * ┌─────┬─────┬─────┐
    * │ foo ┆ bar ┆ ham │
@@ -341,11 +340,11 @@ export interface DataFrame
    * @param columns - column or columns to explode
    * @example
    * ```
-   * >  df = pl.DataFrame({
+   * >  const df = pl.DataFrame({
    * ...    "letters": ["c", "c", "a", "c", "a", "b"],
    * ...    "nrs": [[1, 2], [1, 3], [4, 3], [5, 5, 5], [6], [2, 1, 2]]
-   * ...  })
-   * >  df
+   * ...  });
+   * >  console.log(df.toString());
    * shape: (6, 2)
    * ╭─────────┬────────────╮
    * │ letters ┆ nrs        │
@@ -438,11 +437,11 @@ export interface DataFrame
    * @param predicate - Expression that evaluates to a boolean Series.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
+   * ... });
    * // Filter on one condition
    * > df.filter(pl.col("foo").lt(3))
    * shape: (2, 3)
@@ -477,11 +476,11 @@ export interface DataFrame
    * @param name -Name of the column to find.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
+   * ... });
    * > df.findIdxByName("ham"))
    * 2
    * ```
@@ -503,11 +502,11 @@ export interface DataFrame
    * @example
    * ```
    * > // A horizontal sum operation
-   * > df = pl.DataFrame({
+   * > let df = pl.DataFrame({
    * ...   "a": [2, 1, 3],
    * ...   "b": [1, 2, 3],
    * ...   "c": [1.0, 2.0, 3.0]
-   * ... })
+   * ... });
    * > df.fold((s1, s2) => s1.plus(s2))
    * Series: 'a' [f64]
    * [
@@ -520,7 +519,7 @@ export interface DataFrame
    * ...   "a": [2, 1, 3],
    * ...   "b": [1, 2, 3],
    * ...   "c": [1.0, 2.0, 3.0]
-   * ... })
+   * ... });
    * > df.fold((s1, s2) => s1.zipWith(s1.lt(s2), s2))
    * Series: 'a' [f64]
    * [
@@ -552,12 +551,12 @@ export interface DataFrame
    * @param options.nullEqual Consider null values as equal.
    * @example
    * ```
-   * > df1 = pl.DataFrame({
+   * > const df1 = pl.DataFrame({
    * ...    "foo": [1, 2, 3],
    * ...    "bar": [6.0, 7.0, 8.0],
    * ...    "ham": ['a', 'b', 'c']
    * ... })
-   * > df2 = pl.DataFrame({
+   * > const df2 = pl.DataFrame({
    * ...   "foo": [3, 2, 1],
    * ...   "bar": [8.0, 7.0, 6.0],
    * ...   "ham": ['c', 'b', 'a']
@@ -604,11 +603,11 @@ export interface DataFrame
    * @param length -  Length of the head.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3, 4, 5],
    * ...   "bar": [6, 7, 8, 9, 10],
    * ...   "ham": ['a', 'b', 'c', 'd','e']
-   * ... })
+   * ... });
    * > df.head(3)
    * shape: (3, 3)
    * ╭─────┬─────┬─────╮
@@ -631,12 +630,12 @@ export interface DataFrame
    * @param inPlace - Modify in place
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > x = pl.Series("apple", [10, 20, 30])
+   * ... });
+   * > const x = pl.Series("apple", [10, 20, 30])
    * > df.hStack([x])
    * shape: (3, 4)
    * ╭─────┬─────┬─────┬───────╮
@@ -688,15 +687,15 @@ export interface DataFrame
    * @see {@link JoinOptions}
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6.0, 7.0, 8.0],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > otherDF = pl.DataFrame({
+   * ... });
+   * > const otherDF = pl.DataFrame({
    * ...   "apple": ['x', 'y', 'z'],
    * ...   "ham": ['a', 'b', 'd']
-   * ... })
+   * ... });
    * > df.join(otherDF, {on: 'ham'})
    * shape: (2, 4)
    * ╭─────┬─────┬─────┬───────╮
@@ -841,11 +840,11 @@ export interface DataFrame
    * @param axis - either 0 or 1
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
+   * ... });
    * > df.max()
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
@@ -876,12 +875,12 @@ export interface DataFrame
    * ___
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.median()
+   * ... });
+   * > df.median();
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
    * │ foo ┆ bar ┆ ham  │
@@ -901,13 +900,13 @@ export interface DataFrame
    * @param valueVars - Values to use as value variables.
    * @example
    * ```
-   * > df1 = pl.DataFrame({
+   * > const df1 = pl.DataFrame({
    * ...   'id': [1],
    * ...   'asset_key_1': ['123'],
    * ...   'asset_key_2': ['456'],
    * ...   'asset_key_3': ['abc'],
-   * ... })
-   * > df1.melt('id', ['asset_key_1', 'asset_key_2', 'asset_key_3'])
+   * ... });
+   * > df1.melt('id', ['asset_key_1', 'asset_key_2', 'asset_key_3']);
    * shape: (3, 3)
    * ┌─────┬─────────────┬───────┐
    * │ id  ┆ variable    ┆ value │
@@ -929,12 +928,12 @@ export interface DataFrame
    * @param axis - either 0 or 1
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.min()
+   * ... });
+   * > df.min();
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
    * │ foo ┆ bar ┆ ham  │
@@ -957,12 +956,12 @@ export interface DataFrame
    * ___
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, null, 3],
    * ...   "bar": [6, 7, null],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.nullCount()
+   * ... });
+   * > df.nullCount();
    * shape: (1, 3)
    * ┌─────┬─────┬─────┐
    * │ foo ┆ bar ┆ ham │
@@ -1006,14 +1005,14 @@ export interface DataFrame
    *   @param options.sortColumns Sort the transposed columns by name. Default is by order of discovery.
    *   @example
    * ```
-   *   > df = pl.DataFrame(
+   *   > const df = pl.DataFrame(
    *   ...     {
    *   ...         "foo": ["one", "one", "one", "two", "two", "two"],
    *   ...         "bar": ["A", "B", "C", "A", "B", "C"],
    *   ...         "baz": [1, 2, 3, 4, 5, 6],
    *   ...     }
-   *   ... )
-   *   > df.pivot({values:"baz", index:"foo", columns:"bar"})
+   *   ... );
+   *   > df.pivot({values:"baz", index:"foo", columns:"bar"});
    *   shape: (2, 4)
    *   ┌─────┬─────┬─────┬─────┐
    *   │ foo ┆ A   ┆ B   ┆ C   │
@@ -1071,12 +1070,12 @@ export interface DataFrame
    * Aggregate the columns of this DataFrame to their quantile value.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.quantile(0.5)
+   * ... });
+   * > df.quantile(0.5);
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
    * │ foo ┆ bar ┆ ham  │
@@ -1101,12 +1100,12 @@ export interface DataFrame
    * @param mapping - Key value pairs that map from old name to new name.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.rename({"foo": "apple"})
+   * ... });
+   * > df.rename({"foo": "apple"});
    * ╭───────┬─────┬─────╮
    * │ apple ┆ bar ┆ ham │
    * │ ---   ┆ --- ┆ --- │
@@ -1128,13 +1127,13 @@ export interface DataFrame
    * @param newColumn - New column to insert
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > x = pl.Series("apple", [10, 20, 30])
-   * > df.replaceAtIdx(0, x)
+   * ... });
+   * > const x = pl.Series("apple", [10, 20, 30]);
+   * > df.replaceAtIdx(0, x);
    * shape: (3, 3)
    * ╭───────┬─────┬─────╮
    * │ apple ┆ bar ┆ ham │
@@ -1155,11 +1154,11 @@ export interface DataFrame
    * @param index - row index
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
+   * ... });
    * > df.row(2)
    * [3, 8, 'c']
    * ```
@@ -1176,12 +1175,12 @@ export interface DataFrame
    * @param columns - Column or columns to select.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...     "foo": [1, 2, 3],
    * ...     "bar": [6, 7, 8],
    * ...     "ham": ['a', 'b', 'c']
-   * ...     })
-   * > df.select('foo')
+   * ...     });
+   * > df.select('foo');
    * shape: (3, 1)
    * ┌─────┐
    * │ foo │
@@ -1204,12 +1203,12 @@ export interface DataFrame
    * @param periods - Number of places to shift (may be negative).
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.shift(1)
+   * ... });
+   * > df.shift(1);
    * shape: (3, 3)
    * ┌──────┬──────┬──────┐
    * │ foo  ┆ bar  ┆ ham  │
@@ -1248,12 +1247,12 @@ export interface DataFrame
    * @param opts.fillValue - fill null values with this value.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.shiftAndFill({n:1, fill_value:0})
+   * ... });
+   * > df.shiftAndFill({n:1, fill_value:0});
    * shape: (3, 3)
    * ┌─────┬─────┬─────┐
    * │ foo ┆ bar ┆ ham │
@@ -1290,12 +1289,12 @@ export interface DataFrame
    * @param opts.length - Length of the slice
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6.0, 7.0, 8.0],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.slice(1, 2) // Alternatively `df.slice({offset:1, length:2})`
+   * ... });
+   * > df.slice(1, 2); // Alternatively `df.slice({offset:1, length:2})`
    * shape: (2, 3)
    * ┌─────┬─────┬─────┐
    * │ foo ┆ bar ┆ ham │
@@ -1335,12 +1334,12 @@ export interface DataFrame
    * ___
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "foo": [1, 2, 3],
    * ...   "bar": [6, 7, 8],
    * ...   "ham": ['a', 'b', 'c']
-   * ... })
-   * > df.std()
+   * ... });
+   * > df.std();
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
    * │ foo ┆ bar ┆ ham  │
@@ -1366,11 +1365,11 @@ export interface DataFrame
   /**
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "letters": ["c", "c", "a", "c", "a", "b"],
    * ...   "nrs": [1, 2, 3, 4, 5, 6]
-   * ... })
-   * > df
+   * ... });
+   * > console.log(df.toString());
    * shape: (6, 2)
    * ╭─────────┬─────╮
    * │ letters ┆ nrs │
@@ -1478,11 +1477,11 @@ export interface DataFrame
    *  @param name Name for the struct Series
    *  @example
    *  ```
-   *  > df = pl.DataFrame({
+   *  > const df = pl.DataFrame({
    *  ...   "a": [1, 2, 3, 4, 5],
    *  ...   "b": ["one", "two", "three", "four", "five"],
-   *  ... })
-   *  > df.toStruct("nums")
+   *  ... });
+   *  > df.toStruct("nums");
    *  shape: (5,)
    *  Series: 'nums' [struct[2]{'a': i64, 'b': str}]
    *  [
@@ -1505,7 +1504,7 @@ export interface DataFrame
    * @param options.columnNames Optional generator/iterator that yields column names. Will be used to replace the columns in the DataFrame.
    *
    * @example
-   * > df = pl.DataFrame({"a": [1, 2, 3], "b": [1, 2, 3]})
+   * > const df = pl.DataFrame({"a": [1, 2, 3], "b": [1, 2, 3]});
    * > df.transpose({includeHeader:true})
    * shape: (2, 4)
    * ┌────────┬──────────┬──────────┬──────────┐
@@ -1595,14 +1594,14 @@ export interface DataFrame
       @param names Names of the struct columns that will be decomposed by its fields
       @example
       ```
-      > df = pl.DataFrame({
+      > const df = pl.DataFrame({
       ...   "int": [1, 2],
       ...   "str": ["a", "b"],
       ...   "bool": [true, null],
       ...   "list": [[1, 2], [3]],
       ... })
       ...  .toStruct("my_struct")
-      ...  .toFrame()
+      ...  .toFrame();
       > df
       shape: (2, 1)
       ┌─────────────────────────────┐
@@ -1632,11 +1631,11 @@ export interface DataFrame
    * Aggregate the columns of this DataFrame to their variance value.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * >   "foo": [1, 2, 3],
    * >   "bar": [6, 7, 8],
    * >   "ham": ['a', 'b', 'c']
-   * > })
+   * > });
    * > df.var()
    * shape: (1, 3)
    * ╭─────┬─────┬──────╮
@@ -1654,17 +1653,17 @@ export interface DataFrame
    * @param df - DataFrame to stack.
    * @example
    * ```
-   * > df1 = pl.DataFrame({
+   * > const df1 = pl.DataFrame({
    * ...   "foo": [1, 2],
    * ...   "bar": [6, 7],
    * ...   "ham": ['a', 'b']
-   * ... })
-   * > df2 = pl.DataFrame({
+   * ... });
+   * > const df2 = pl.DataFrame({
    * ...   "foo": [3, 4],
    * ...   "bar": [8 , 9],
    * ...   "ham": ['c', 'd']
-   * ... })
-   * > df1.vstack(df2)
+   * ... });
+   * > df1.vstack(df2);
    * shape: (4, 3)
    * ╭─────┬─────┬─────╮
    * │ foo ┆ bar ┆ ham │
@@ -1703,6 +1702,91 @@ export interface DataFrame
   withRowCount(name?: string): DataFrame;
   /** @see {@link filter} */
   where(predicate: any): DataFrame;
+  /**
+    Upsample a DataFrame at a regular frequency.
+
+    The `every` and `offset` arguments are created with the following string language:
+    - 1ns   (1 nanosecond)
+    - 1us   (1 microsecond)
+    - 1ms   (1 millisecond)
+    - 1s    (1 second)
+    - 1m    (1 minute)
+    - 1h    (1 hour)
+    - 1d    (1 calendar day)
+    - 1w    (1 calendar week)
+    - 1mo   (1 calendar month)
+    - 1q    (1 calendar quarter)
+    - 1y    (1 calendar year)
+    - 1i    (1 index count)
+
+    Or combine them:
+    - "3d12h4m25s" # 3 days, 12 hours, 4 minutes, and 25 seconds
+
+    By "calendar day", we mean the corresponding time on the next day (which may not be 24 hours, due to daylight savings). 
+    Similarly for "calendar week", "calendar month", "calendar quarter", and "calendar year".
+
+    Parameters
+    ----------
+    @param timeColumn Time column will be used to determine a date range.
+                        Note that this column has to be sorted for the output to make sense.
+    @param every Interval will start 'every' duration.
+    @param offset Change the start of the date range by this offset.
+    @param by First group by these columns and then upsample for every group.
+    @param maintainOrder Keep the ordering predictable. This is slower.
+
+    Returns
+    -------
+    DataFrame
+        Result will be sorted by `timeColumn` (but note that if `by` columns are passed, it will only be sorted within each `by` group).
+
+    Examples
+    --------
+    Upsample a DataFrame by a certain interval.
+
+    >>> const df = pl.DataFrame({
+            "date": [
+                new Date(2024, 1, 1),
+                new Date(2024, 3, 1),
+                new Date(2024, 4, 1),
+                new Date(2024, 5, 1),
+            ],
+            "groups": ["A", "B", "A", "B"],
+            "values": [0, 1, 2, 3],
+         })
+          .withColumn(pl.col("date").cast(pl.Date).alias("date"))
+          .sort("date");
+
+    >>> df.upsample({timeColumn: "date", every: "1mo", offset: "0ns", by: "groups", maintainOrder: true})
+          .select(pl.col("*").forwardFill());
+shape: (7, 3)
+┌────────────┬────────┬────────┐
+│ date       ┆ groups ┆ values │
+│ ---        ┆ ---    ┆ ---    │
+│ date       ┆ str    ┆ f64    │
+╞════════════╪════════╪════════╡
+│ 2024-02-01 ┆ A      ┆ 0.0    │
+│ 2024-03-01 ┆ A      ┆ 0.0    │
+│ 2024-04-01 ┆ A      ┆ 0.0    │
+│ 2024-05-01 ┆ A      ┆ 2.0    │
+│ 2024-04-01 ┆ B      ┆ 1.0    │
+│ 2024-05-01 ┆ B      ┆ 1.0    │
+│ 2024-06-01 ┆ B      ┆ 3.0    │
+└────────────┴────────┴────────┘
+  */
+  upsample(
+    timeColumn: string,
+    every: string,
+    offset?: string,
+    by?: string | string[],
+    maintainOrder?: boolean,
+  ): DataFrame;
+  upsample(opts: {
+    timeColumn: string;
+    every: string;
+    offset?: string;
+    by?: string | string[];
+    maintainOrder?: boolean;
+  }): DataFrame;
 }
 
 function prepareOtherArg(anyValue: any): Series {
@@ -1966,6 +2050,30 @@ export const _DataFrame = (_df: any): DataFrame => {
         by,
       );
     },
+    upsample(opts, every?, offset?, by?, maintainOrder?) {
+      let timeColumn;
+      if (typeof opts === "string") {
+        timeColumn = opts;
+      } else {
+        timeColumn = opts.timeColumn;
+        by = opts.by;
+        offset = opts.offset;
+        every = opts.every;
+        maintainOrder = opts.maintainOrder ?? false;
+      }
+
+      if (typeof by === "string") {
+        by = [by];
+      } else {
+        by = by ?? [];
+      }
+
+      offset = offset ?? "0ns";
+
+      return _DataFrame(
+        _df.upsample(by, timeColumn, every, offset, maintainOrder),
+      );
+    },
     hashRows(obj: any = 0n, k1 = 1n, k2 = 2n, k3 = 3n) {
       if (typeof obj === "number" || typeof obj === "bigint") {
         return _Series(
diff --git a/polars/lazy/expr/index.ts b/polars/lazy/expr/index.ts
index e1e28d3ff..86c88af28 100644
--- a/polars/lazy/expr/index.ts
+++ b/polars/lazy/expr/index.ts
@@ -66,10 +66,10 @@ export interface Expr
    * @see {@link Expr.as}
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "a": [1, 2, 3],
    * ...   "b": ["a", "b", None],
-   * ... })
+   * ... });
    * > df
    * shape: (3, 2)
    * ╭─────┬──────╮
@@ -150,12 +150,12 @@ export interface Expr
    * @param columns Column(s) to exclude from selection
    * @example
    * ```
-   *  >df = pl.DataFrame({
+   *  > const df = pl.DataFrame({
    *  ...   "a": [1, 2, 3],
    *  ...   "b": ["a", "b", None],
    *  ...   "c": [None, 2, 1],
-   *  ...})
-   *  >df
+   *  ...});
+   *  > df
    *  shape: (3, 3)
    *  ╭─────┬──────┬──────╮
    *  │ a   ┆ b    ┆ c    │
@@ -168,9 +168,9 @@ export interface Expr
    *  ├╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌┤
    *  │ 3   ┆ null ┆ 1    │
    *  ╰─────┴──────┴──────╯
-   *  >df.select(
+   *  > df.select(
    *  ...   pl.col("*").exclude("b"),
-   *  ... )
+   *  ... );
    * shape: (3, 2)
    * ╭─────┬──────╮
    * │ a   ┆ c    │
@@ -253,13 +253,13 @@ export interface Expr
    * @returns Expr that evaluates to a Boolean Series.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "sets": [[1, 2, 3], [1, 2], [9, 10]],
    * ...    "optional_members": [1, 2, 3]
-   * ... })
+   * ... });
    * > df.select(
    * ...   pl.col("optional_members").isIn("sets").alias("contains")
-   * ... )
+   * ... );
    * shape: (3, 1)
    * ┌──────────┐
    * │ contains │
@@ -294,15 +294,15 @@ export interface Expr
    * With `keepName` we can keep the original name of the column
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "a": [1, 2, 3],
    * ...   "b": ["a", "b", None],
-   * ... })
+   * ... });
    *
    * > df
    * ...   .groupBy("a")
    * ...   .agg(pl.col("b").list())
-   * ...   .sort({by:"a"})
+   * ...   .sort({by:"a"});
    *
    * shape: (3, 2)
    * ╭─────┬────────────╮
@@ -374,13 +374,13 @@ export interface Expr
    *
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...  "groups": [1, 1, 2, 2, 1, 2, 3, 3, 1],
    * ...  "values": [1, 2, 3, 4, 5, 6, 7, 8, 8],
-   * ... })
+   * ... });
    * > df.select(
    * ...     pl.col("groups").sum().over("groups")
-   * ... )
+   * ... );
    *     ╭────────┬────────╮
    *     │ groups ┆ values │
    *     │ ---    ┆ ---    │
@@ -416,12 +416,12 @@ export interface Expr
    * Add a prefix the to root column name of the expression.
    * @example
    * ```
-   * > df = pl.DataFrame({
+   * > const df = pl.DataFrame({
    * ...   "A": [1, 2, 3, 4, 5],
    * ...   "fruits": ["banana", "banana", "apple", "apple", "banana"],
    * ...   "B": [5, 4, 3, 2, 1],
    * ...   "cars": ["beetle", "audi", "beetle", "beetle", "beetle"],
-   * ... })
+   * ... });
    * shape: (5, 4)
    * ╭─────┬──────────┬─────┬──────────╮
    * │ A   ┆ fruits   ┆ B   ┆ cars     │
@@ -439,7 +439,7 @@ export interface Expr
    * │ 5   ┆ "banana" ┆ 1   ┆ "beetle" │
    * ╰─────┴──────────┴─────┴──────────╯
    * > df.select(
-   * ...   pl.all().reverse().prefix("reverse_"),
+   * ...   pl.col("*").reverse().prefix("reverse_"),
    * ... )
    * shape: (5, 8)
    * ╭───────────┬────────────────┬───────────┬──────────────╮
@@ -528,8 +528,7 @@ export interface Expr
 
       Parameters
       ----------
-      @param by
-          The column(s) used for sorting.
+      @param by The column(s) used for sorting.
       @param reverse
           false -> order from small to large.
           true -> order from large to small.
diff --git a/yarn.lock b/yarn.lock
index 57c5028d3..29a979928 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -408,18 +408,18 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@biomejs/biome@npm:^1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/biome@npm:1.5.1"
-  dependencies:
-    "@biomejs/cli-darwin-arm64": 1.5.1
-    "@biomejs/cli-darwin-x64": 1.5.1
-    "@biomejs/cli-linux-arm64": 1.5.1
-    "@biomejs/cli-linux-arm64-musl": 1.5.1
-    "@biomejs/cli-linux-x64": 1.5.1
-    "@biomejs/cli-linux-x64-musl": 1.5.1
-    "@biomejs/cli-win32-arm64": 1.5.1
-    "@biomejs/cli-win32-x64": 1.5.1
+"@biomejs/biome@npm:^1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/biome@npm:1.5.3"
+  dependencies:
+    "@biomejs/cli-darwin-arm64": 1.5.3
+    "@biomejs/cli-darwin-x64": 1.5.3
+    "@biomejs/cli-linux-arm64": 1.5.3
+    "@biomejs/cli-linux-arm64-musl": 1.5.3
+    "@biomejs/cli-linux-x64": 1.5.3
+    "@biomejs/cli-linux-x64-musl": 1.5.3
+    "@biomejs/cli-win32-arm64": 1.5.3
+    "@biomejs/cli-win32-x64": 1.5.3
   dependenciesMeta:
     "@biomejs/cli-darwin-arm64":
       optional: true
@@ -439,62 +439,62 @@ __metadata:
       optional: true
   bin:
     biome: bin/biome
-  checksum: d8dadc2e9b06544a109944b23b812f9da0da456b35d8661518665a295cecd4914940253182f135f34aa7e17d09e4d2d85aa785595ae60aa94fa6aadc8c2ce207
+  checksum: 5155dc05ca3a9fd0228eb74df4f21d0ab311e4b02452c6b3dc5615825eab402df6824992014ff19f82bed49fd286e0001ebe608efdba71a41f3f6c06305b1d7c
   languageName: node
   linkType: hard
 
-"@biomejs/cli-darwin-arm64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-darwin-arm64@npm:1.5.1"
+"@biomejs/cli-darwin-arm64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-darwin-arm64@npm:1.5.3"
   conditions: os=darwin & cpu=arm64
   languageName: node
   linkType: hard
 
-"@biomejs/cli-darwin-x64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-darwin-x64@npm:1.5.1"
+"@biomejs/cli-darwin-x64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-darwin-x64@npm:1.5.3"
   conditions: os=darwin & cpu=x64
   languageName: node
   linkType: hard
 
-"@biomejs/cli-linux-arm64-musl@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-linux-arm64-musl@npm:1.5.1"
+"@biomejs/cli-linux-arm64-musl@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-linux-arm64-musl@npm:1.5.3"
   conditions: os=linux & cpu=arm64 & libc=musl
   languageName: node
   linkType: hard
 
-"@biomejs/cli-linux-arm64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-linux-arm64@npm:1.5.1"
+"@biomejs/cli-linux-arm64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-linux-arm64@npm:1.5.3"
   conditions: os=linux & cpu=arm64 & libc=glibc
   languageName: node
   linkType: hard
 
-"@biomejs/cli-linux-x64-musl@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-linux-x64-musl@npm:1.5.1"
+"@biomejs/cli-linux-x64-musl@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-linux-x64-musl@npm:1.5.3"
   conditions: os=linux & cpu=x64 & libc=musl
   languageName: node
   linkType: hard
 
-"@biomejs/cli-linux-x64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-linux-x64@npm:1.5.1"
+"@biomejs/cli-linux-x64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-linux-x64@npm:1.5.3"
   conditions: os=linux & cpu=x64 & libc=glibc
   languageName: node
   linkType: hard
 
-"@biomejs/cli-win32-arm64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-win32-arm64@npm:1.5.1"
+"@biomejs/cli-win32-arm64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-win32-arm64@npm:1.5.3"
   conditions: os=win32 & cpu=arm64
   languageName: node
   linkType: hard
 
-"@biomejs/cli-win32-x64@npm:1.5.1":
-  version: 1.5.1
-  resolution: "@biomejs/cli-win32-x64@npm:1.5.1"
+"@biomejs/cli-win32-x64@npm:1.5.3":
+  version: 1.5.3
+  resolution: "@biomejs/cli-win32-x64@npm:1.5.3"
   conditions: os=win32 & cpu=x64
   languageName: node
   linkType: hard
@@ -824,12 +824,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@napi-rs/cli@npm:^2.17.0":
-  version: 2.17.0
-  resolution: "@napi-rs/cli@npm:2.17.0"
+"@napi-rs/cli@npm:^2.18.0":
+  version: 2.18.0
+  resolution: "@napi-rs/cli@npm:2.18.0"
   bin:
     napi: scripts/index.js
-  checksum: f86f5e2ecea589605dd245e647f5de9e60b533911ad3ef59b8c92cddbb9e127696b1d21255c50a857a8a4212418ba0a91800d6051aeffe4380720cda66961a63
+  checksum: eadff1dda564416b66db44f5ea7088712f8cf66f6677082197e6d3ce5a57d9eabeb0d091b4d1685e8a4bd275ff1de684fca1ae84edd0f66dac82cb328acc068c
   languageName: node
   linkType: hard
 
@@ -991,13 +991,13 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/jest@npm:^29.5.11":
-  version: 29.5.11
-  resolution: "@types/jest@npm:29.5.11"
+"@types/jest@npm:^29.5.12":
+  version: 29.5.12
+  resolution: "@types/jest@npm:29.5.12"
   dependencies:
     expect: ^29.0.0
     pretty-format: ^29.0.0
-  checksum: f892a06ec9f0afa9a61cd7fa316ec614e21d4df1ad301b5a837787e046fcb40dfdf7f264a55e813ac6b9b633cb9d366bd5b8d1cea725e84102477b366df23fdd
+  checksum: 19b1efdeed9d9a60a81edc8226cdeae5af7479e493eaed273e01243891c9651f7b8b4c08fc633a7d0d1d379b091c4179bbaa0807af62542325fd72f2dd17ce1c
   languageName: node
   linkType: hard
 
@@ -1008,12 +1008,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/node@npm:^20.10.8":
-  version: 20.10.8
-  resolution: "@types/node@npm:20.10.8"
+"@types/node@npm:^20.11.17":
+  version: 20.11.17
+  resolution: "@types/node@npm:20.11.17"
   dependencies:
     undici-types: ~5.26.4
-  checksum: ce9b7ee545b3605f667be2ea900e38ab58d7b561192a7342443e5d7f61c44fd9d016eac48e95d3011f090ceea65a727e83a31d51fabdd9fc20ff9992edcbc682
+  checksum: 59c0dde187120adc97da30063c86511664b24b50fe777abfe1f557c217d0a0b84a68aaab5ef8ac44f5c2986b3f9cd605a15fa6e4f31195e594da96bbe9617c20
   languageName: node
   linkType: hard
 
@@ -3087,17 +3087,17 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "nodejs-polars@workspace:."
   dependencies:
-    "@biomejs/biome": ^1.5.1
-    "@napi-rs/cli": ^2.17.0
+    "@biomejs/biome": ^1.5.3
+    "@napi-rs/cli": ^2.18.0
     "@types/chance": ^1.1.6
-    "@types/jest": ^29.5.11
-    "@types/node": ^20.10.8
+    "@types/jest": ^29.5.12
+    "@types/node": ^20.11.17
     chance: ^1.1.11
     jest: ^29.7.0
     source-map-support: ^0.5.21
-    ts-jest: ^29.1.1
+    ts-jest: ^29.1.2
     ts-node: ^10.9.2
-    typedoc: ^0.25.7
+    typedoc: ^0.25.8
     typescript: 5.3.3
   languageName: unknown
   linkType: soft
@@ -3758,9 +3758,9 @@ __metadata:
   languageName: node
   linkType: hard
 
-"ts-jest@npm:^29.1.1":
-  version: 29.1.1
-  resolution: "ts-jest@npm:29.1.1"
+"ts-jest@npm:^29.1.2":
+  version: 29.1.2
+  resolution: "ts-jest@npm:29.1.2"
   dependencies:
     bs-logger: 0.x
     fast-json-stable-stringify: 2.x
@@ -3787,7 +3787,7 @@ __metadata:
       optional: true
   bin:
     ts-jest: cli.js
-  checksum: a8c9e284ed4f819526749f6e4dc6421ec666f20ab44d31b0f02b4ed979975f7580b18aea4813172d43e39b29464a71899f8893dd29b06b4a351a3af8ba47b402
+  checksum: a0ce0affc1b716c78c9ab55837829c42cb04b753d174a5c796bb1ddf9f0379fc20647b76fbe30edb30d9b23181908138d6b4c51ef2ae5e187b66635c295cefd5
   languageName: node
   linkType: hard
 
@@ -3843,9 +3843,9 @@ __metadata:
   languageName: node
   linkType: hard
 
-"typedoc@npm:^0.25.7":
-  version: 0.25.7
-  resolution: "typedoc@npm:0.25.7"
+"typedoc@npm:^0.25.8":
+  version: 0.25.8
+  resolution: "typedoc@npm:0.25.8"
   dependencies:
     lunr: ^2.3.9
     marked: ^4.3.0
@@ -3855,7 +3855,7 @@ __metadata:
     typescript: 4.6.x || 4.7.x || 4.8.x || 4.9.x || 5.0.x || 5.1.x || 5.2.x || 5.3.x
   bin:
     typedoc: bin/typedoc
-  checksum: 49c3bf923a3c9401b549e5843f8efaaac8fa28f8ec6bd8617187b5d9ba9932a3fa63dc3863b82389507ffc7d92908af0dce33780fffb4970cd0833274f6fa0cf
+  checksum: c81992d791ef267e5f94ce0bf0ee98452ac772f4a12a96ad3b18520e7a1f9ba5f6908e48d5e73330fdedb7bfd0b9e0a74073afa5ef75775f76f1c6f3f3fce3a3
   languageName: node
   linkType: hard