| /** | |
|  * @fileoverview Rule to disallow `parseInt()` in favor of binary, octal, and hexadecimal literals | |
|  * @author Annie Zhang, Henry Zhu | |
|  */ | |
| 
 | |
| "use strict"; | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Requirements | |
| //------------------------------------------------------------------------------ | |
|  | |
| const astUtils = require("./utils/ast-utils"); | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Helpers | |
| //------------------------------------------------------------------------------ | |
|  | |
| const radixMap = new Map([ | |
|     [2, { system: "binary", literalPrefix: "0b" }], | |
|     [8, { system: "octal", literalPrefix: "0o" }], | |
|     [16, { system: "hexadecimal", literalPrefix: "0x" }] | |
| ]); | |
| 
 | |
| /** | |
|  * Checks to see if a CallExpression's callee node is `parseInt` or | |
|  * `Number.parseInt`. | |
|  * @param {ASTNode} calleeNode The callee node to evaluate. | |
|  * @returns {boolean} True if the callee is `parseInt` or `Number.parseInt`, | |
|  * false otherwise. | |
|  */ | |
| function isParseInt(calleeNode) { | |
|     return ( | |
|         astUtils.isSpecificId(calleeNode, "parseInt") || | |
|         astUtils.isSpecificMemberAccess(calleeNode, "Number", "parseInt") | |
|     ); | |
| } | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
|  | |
| /** @type {import('../shared/types').Rule} */ | |
| module.exports = { | |
|     meta: { | |
|         type: "suggestion", | |
| 
 | |
|         docs: { | |
|             description: "Disallow `parseInt()` and `Number.parseInt()` in favor of binary, octal, and hexadecimal literals", | |
|             recommended: false, | |
|             url: "https://eslint.org/docs/latest/rules/prefer-numeric-literals" | |
|         }, | |
| 
 | |
|         schema: [], | |
| 
 | |
|         messages: { | |
|             useLiteral: "Use {{system}} literals instead of {{functionName}}()." | |
|         }, | |
| 
 | |
|         fixable: "code" | |
|     }, | |
| 
 | |
|     create(context) { | |
|         const sourceCode = context.sourceCode; | |
| 
 | |
|         //---------------------------------------------------------------------- | |
|         // Public | |
|         //---------------------------------------------------------------------- | |
|  | |
|         return { | |
| 
 | |
|             "CallExpression[arguments.length=2]"(node) { | |
|                 const [strNode, radixNode] = node.arguments, | |
|                     str = astUtils.getStaticStringValue(strNode), | |
|                     radix = radixNode.value; | |
| 
 | |
|                 if ( | |
|                     str !== null && | |
|                     astUtils.isStringLiteral(strNode) && | |
|                     radixNode.type === "Literal" && | |
|                     typeof radix === "number" && | |
|                     radixMap.has(radix) && | |
|                     isParseInt(node.callee) | |
|                 ) { | |
| 
 | |
|                     const { system, literalPrefix } = radixMap.get(radix); | |
| 
 | |
|                     context.report({ | |
|                         node, | |
|                         messageId: "useLiteral", | |
|                         data: { | |
|                             system, | |
|                             functionName: sourceCode.getText(node.callee) | |
|                         }, | |
|                         fix(fixer) { | |
|                             if (sourceCode.getCommentsInside(node).length) { | |
|                                 return null; | |
|                             } | |
| 
 | |
|                             const replacement = `${literalPrefix}${str}`; | |
| 
 | |
|                             if (+replacement !== parseInt(str, radix)) { | |
| 
 | |
|                                 /* | |
|                                  * If the newly-produced literal would be invalid, (e.g. 0b1234), | |
|                                  * or it would yield an incorrect parseInt result for some other reason, don't make a fix. | |
|                                  * | |
|                                  * If `str` had numeric separators, `+replacement` will evaluate to `NaN` because unary `+` | |
|                                  * per the specification doesn't support numeric separators. Thus, the above condition will be `true` | |
|                                  * (`NaN !== anything` is always `true`) regardless of the `parseInt(str, radix)` value. | |
|                                  * Consequently, no autofixes will be made. This is correct behavior because `parseInt` also | |
|                                  * doesn't support numeric separators, but it does parse part of the string before the first `_`, | |
|                                  * so the autofix would be invalid: | |
|                                  * | |
|                                  *   parseInt("1_1", 2) // === 1 | |
|                                  *   0b1_1 // === 3 | |
|                                  */ | |
|                                 return null; | |
|                             } | |
| 
 | |
|                             const tokenBefore = sourceCode.getTokenBefore(node), | |
|                                 tokenAfter = sourceCode.getTokenAfter(node); | |
|                             let prefix = "", | |
|                                 suffix = ""; | |
| 
 | |
|                             if ( | |
|                                 tokenBefore && | |
|                                 tokenBefore.range[1] === node.range[0] && | |
|                                 !astUtils.canTokensBeAdjacent(tokenBefore, replacement) | |
|                             ) { | |
|                                 prefix = " "; | |
|                             } | |
| 
 | |
|                             if ( | |
|                                 tokenAfter && | |
|                                 node.range[1] === tokenAfter.range[0] && | |
|                                 !astUtils.canTokensBeAdjacent(replacement, tokenAfter) | |
|                             ) { | |
|                                 suffix = " "; | |
|                             } | |
| 
 | |
|                             return fixer.replaceText(node, `${prefix}${replacement}${suffix}`); | |
|                         } | |
|                     }); | |
|                 } | |
|             } | |
|         }; | |
|     } | |
| };
 |