Add fromMap API

jridgewell · Apr 27, 2022 · 6d768ab · 6d768ab
1 parent 2464c6c
commit 6d768ab
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Showing 5 changed files with 151 additions and 9 deletions.
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -67,6 +67,7 @@
   },
   "dependencies": {
     "@jridgewell/set-array": "^1.0.0",
-    "@jridgewell/sourcemap-codec": "^1.4.10"
+    "@jridgewell/sourcemap-codec": "^1.4.10",
+    "@jridgewell/trace-mapping": "^0.3.9"
   }
 }
diff --git a/rollup.config.js b/rollup.config.js
@@ -14,6 +14,7 @@ function configure(esm) {
           globals: {
             '@jridgewell/set-array': 'setArray',
             '@jridgewell/sourcemap-codec': 'sourcemapCodec',
+            '@jridgewell/trace-mapping': 'traceMapping',
           },
         },
     plugins: [

diff --git a/src/gen-mapping.ts b/src/gen-mapping.ts
@@ -1,6 +1,8 @@
 import { SetArray, put } from '@jridgewell/set-array';
 import { encode } from '@jridgewell/sourcemap-codec';
+import { TraceMap, decodedMappings } from '@jridgewell/trace-mapping';
 
+import type { SourceMapInput } from '@jridgewell/trace-mapping';
 import type { SourceMapSegment } from './sourcemap-segment';
 import type { DecodedSourceMap, EncodedSourceMap, Pos, Mapping } from './types';
 
@@ -96,6 +98,11 @@ export let decodedMap: (map: GenMapping) => DecodedSourceMap;
  */
 export let encodedMap: (map: GenMapping) => EncodedSourceMap;
 
+/**
+ * Constructs a new GenMapping, using the already present mappings of the input.
+ */
+export let fromMap: (input: SourceMapInput) => GenMapping;
+
 /**
  * Returns an array of high-level mapping objects for every recorded segment, which could then be
  * passed to the `source-map` library.
@@ -128,7 +135,7 @@ export class GenMapping {
       } = map;
 
       const line = getLine(mappings, genLine);
-      if (source == null) {
+      if (!source) {
         const seg: SourceMapSegment = [genColumn];
         const index = getColumnIndex(line, genColumn, seg);
         return insert(line, index, seg);
@@ -222,6 +229,18 @@ export class GenMapping {
 
       return out;
     };
+
+    fromMap = (input) => {
+      const map = new TraceMap(input);
+      const gen = new GenMapping({ file: map.file, sourceRoot: map.sourceRoot });
+
+      putAll(gen._names, map.names);
+      putAll(gen._sources, map.sources as string[]);
+      gen._sourcesContent = map.sourcesContent || map.sources.map(() => null);
+      gen._mappings = decodedMappings(map) as GenMapping['_mappings'];
+
+      return gen;
+    };
   }
 }
 
@@ -274,9 +293,12 @@ function compareNum(a: number, b: number): number {
 }
 
 function insert<T>(array: T[], index: number, value: T) {
-  if (index === -1) return;
   for (let i = array.length; i > index; i--) {
     array[i] = array[i - 1];
   }
   array[index] = value;
 }
+
+function putAll(strarr: SetArray, array: string[]) {
+  for (let i = 0; i < array.length; i++) put(strarr, array[i]);
+}
diff --git a/test/gen-mapping.test.js b/test/gen-mapping.test.js
@@ -6,6 +6,7 @@ const {
   decodedMap,
   encodedMap,
   allMappings,
+  fromMap,
 } = require('..');
 const assert = require('assert');
 
@@ -430,4 +431,124 @@ describe('GenMapping', () => {
       ]);
     });
   });
+
+  describe('fromMap', () => {
+    it('copies version', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.strictEqual(decodedMap(map).version, 3);
+    });
+
+    it('copies file name', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        file: 'output.js',
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.strictEqual(decodedMap(map).file, 'output.js');
+    });
+
+    it('copies sourceRoot', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sourceRoot: 'foo/',
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.strictEqual(decodedMap(map).sourceRoot, 'foo/');
+    });
+
+    it('copies sources', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).sources, ['input.js']);
+    });
+
+    it('copies sourcesContent', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: ['input'],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).sourcesContent, ['input']);
+    });
+
+    it('creates sourcesContent', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        mappings: [],
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).sourcesContent, [null]);
+    });
+
+    it('copies names', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: ['foo'],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [[[0, 0, 0, 0, 0]]],
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).names, ['foo']);
+    });
+
+    it('copies decoded mappings', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: [[[1, 0, 2, 3, 0]]],
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).mappings, [[[1, 0, 2, 3, 0]]]);
+    });
+
+    it('copies encoded mappings', () => {
+      const input = /** @type {import('@jridgewell/trace-mapping').DecodedSourceMap} */ ({
+        version: 3,
+        names: [],
+        sources: ['input.js'],
+        sourcesContent: [],
+        mappings: 'CAEGA',
+      });
+      const map = fromMap(input);
+
+      assert.deepEqual(decodedMap(map).mappings, [[[1, 0, 2, 3, 0]]]);
+    });
+  });
 });