⭐ feat(rules/number-literal-format): add fix

src/rules/numberLiteralFormatRule.ts

@@ -25,6 +25,7 @@ export class Rule extends Lint.Rules.AbstractRule {
     /* tslint:disable:object-literal-sort-keys */
     public static metadata: Lint.IRuleMetadata = {
         ruleName: "number-literal-format",
+        hasFix: true,
         description:
             "Checks that decimal literals should begin with '0.' instead of just '.', and should not end with a trailing '0'.",
         optionsDescription: "Not configurable.",
@@ -63,6 +64,7 @@ function walk(ctx: Lint.WalkContext<void>): void {
     function check(node: ts.NumericLiteral): void {
         // Apparently the number literal '0.0' has a '.text' of '0', so use '.getText()' instead.
         const text = node.getText(sourceFile);
+        const start = node.getStart();
 
         if (text.length <= 1) {
             return;
@@ -72,8 +74,14 @@ function walk(ctx: Lint.WalkContext<void>): void {
             // Hex/octal/binary number can't have decimal point or exponent, so no other errors possible.
             switch (text[1]) {
                 case "x":
-                    if (!isUpperCase(text.slice(2))) {
-                        ctx.addFailureAtNode(node, Rule.FAILURE_STRING_NOT_UPPERCASE);
+                    // strip "0x"
+                    const hexNumber = text.slice(2);
+                    if (!isUpperCase(hexNumber)) {
+                        ctx.addFailureAtNode(
+                            node,
+                            Rule.FAILURE_STRING_NOT_UPPERCASE,
+                            Lint.Replacement.replaceNode(node, `0x${hexNumber.toUpperCase()}`),
+                        );
                     }
                     return;
                 case "o":
@@ -82,35 +90,60 @@ function walk(ctx: Lint.WalkContext<void>): void {
                 case ".":
                     break;
                 default:
-                    ctx.addFailureAtNode(node, Rule.FAILURE_STRING_LEADING_0);
+                    ctx.addFailureAtNode(
+                        node,
+                        Rule.FAILURE_STRING_LEADING_0,
+                        Lint.Replacement.deleteFromTo(start, start + /^0+/.exec(text)![0].length),
+                    );
                     return;
             }
         }
 
-        const [num, exp] = text.split(/e/i);
+        const [num, exp = ""] = text.split(/e/i);
+        const [integer, float = ""] = num.split(".");
+        const match = /(\.)([1-9]*)(0+)/.exec(num);
+        const [dot = "", numbers = "", zeroes = ""] = Array.isArray(match) ? match.slice(1) : [];
+
         if (exp !== undefined && (exp.startsWith("-0") || exp.startsWith("0"))) {
-            ctx.addFailureAt(node.getEnd() - exp.length, exp.length, Rule.FAILURE_STRING_LEADING_0);
+            const expStart = start + num.length + 1; // position of exp part
+            const expNumberStart = /\D/.test(exp.charAt(0)) ? expStart + 1 : expStart; // do not remove "-" or "+"
+            ctx.addFailureAt(
+                node.getEnd() - exp.length,
+                exp.length,
+                Rule.FAILURE_STRING_LEADING_0,
+                Lint.Replacement.deleteFromTo(
+                    expNumberStart,
+                    expNumberStart + /0+/.exec(exp)![0].length,
+                ),
+            );
         }
 
         if (!num.includes(".")) {
             return;
-        }
-
-        if (num.startsWith(".")) {
-            fail(Rule.FAILURE_STRING_LEADING_DECIMAL);
-        }
-
-        if (num.endsWith(".")) {
-            fail(Rule.FAILURE_STRING_TRAILING_DECIMAL);
+        } else if (num.startsWith(".")) {
+            // .1 -> 0.1
+            fail(Rule.FAILURE_STRING_LEADING_DECIMAL, Lint.Replacement.appendText(start, "0"));
+        } else if (num.endsWith(".")) {
+            // 1. -> 1
+            fail(
+                Rule.FAILURE_STRING_TRAILING_DECIMAL,
+                Lint.Replacement.deleteText(start + num.length - 1, 1),
+            );
         }
 
         // Allow '10', but not '1.0'
-        if (num.endsWith("0")) {
-            fail(Rule.FAILURE_STRING_TRAILING_0);
+        if (float.endsWith("0")) {
+            // 1.0 -> 1
+            const offset = numbers.length > 0 ? dot.length + numbers.length : 0;
+            const length = (numbers.length > 0 ? 0 : dot.length) + zeroes.length;
+            fail(
+                Rule.FAILURE_STRING_TRAILING_0,
+                Lint.Replacement.deleteText(start + integer.length + offset, length),
+            );
         }
 
-        function fail(message: string): void {
-            ctx.addFailureAt(node.getStart(sourceFile), num.length, message);
+        function fail(message: string, fix?: Lint.Replacement | Lint.Replacement[]): void {
+            ctx.addFailureAt(node.getStart(sourceFile), num.length, message, fix);
         }
     }
 }

test/rules/number-literal-format/test.ts.fix

@@ -0,0 +1,26 @@
+0;
+0.5;
+10;
+1.1e10;
+
+-6000;
+
+-777;
+
+-0;
+
+-0.9;
+
+-0.2;
+
+-0.5;
+
+-123e3;
+
+-145E4;
+
+-1467e-8;
+
+-189e10;
+
+-0xDEADBEEF;

test/rules/number-literal-format/test.ts.lint

@@ -3,38 +3,41 @@
 10;
 1.1e10;
 
-01;
-~~ [leading-0]
+-0000006000;
+ ~~~~~~~~~~ [leading-0]
 
-1.
-~~ [trailing-decimal]
+-777.;
+ ~~~~ [trailing-decimal]
 
-0.0;
-~~~ [trailing-0]
-0.50;
-~~~~ [trailing-0]
+-0.000;
+ ~~~~~ [trailing-0]
 
-.5;
-~~ [leading-decimal]
+-0.90000;
+ ~~~~~~~ [trailing-0]
 
-.50;
-~~~ [trailing-0]
-~~~ [leading-decimal]
+-.2;
+ ~~ [leading-decimal]
 
-1e01;
-  ~~ [leading-0]
-1E01;
-  ~~ [leading-0]
-1e-01;
-  ~~~ [leading-0]
-1.0e10;
-~~~ [trailing-0]
+-.50000;
+ ~~~~~~ [trailing-0]
+ ~~~~~~ [leading-decimal]
 
-0xDEAdBEEF;
-~~~~~~~~~~ [uppercase]
+-123e0003;
+     ~~~~ [leading-0]
 
+-145E0004;
+     ~~~~ [leading-0]
+
+-1467e-0008;
+      ~~~~~ [leading-0]
+
+-189.000e10;
+ ~~~~~~~ [trailing-0]
+
+-0xDEAdBEEF;
+ ~~~~~~~~~~ [uppercase]
 [leading-0]: Number literal should not have a leading '0'.
 [trailing-0]: Number literal should not have a trailing '0'.
 [trailing-decimal]: Number literal should not end in '.'.
 [leading-decimal]: Number literal should begin with '0.' and not just '.'.
-[uppercase]: Hexadecimal number literal should be uppercase.
+[uppercase]: Hexadecimal number literal should be uppercase.