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