69 lines
1.4 KiB
Plaintext
69 lines
1.4 KiB
Plaintext
/**
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* @fileoverview Disallow sparse arrays
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* @author Nicholas C. Zakas
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*/
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"use strict";
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const astUtils = require("./utils/ast-utils");
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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: "problem",
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docs: {
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description: "Disallow sparse arrays",
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recommended: true,
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url: "https://eslint.org/docs/latest/rules/no-sparse-arrays",
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},
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schema: [],
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messages: {
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unexpectedSparseArray: "Unexpected comma in middle of array.",
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},
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},
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create(context) {
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//--------------------------------------------------------------------------
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// Public
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//--------------------------------------------------------------------------
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return {
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ArrayExpression(node) {
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if (!node.elements.includes(null)) {
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return;
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}
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const { sourceCode } = context;
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let commaToken;
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for (const [index, element] of node.elements.entries()) {
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if (index === node.elements.length - 1 && element) {
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return;
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}
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commaToken = sourceCode.getTokenAfter(
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element ?? commaToken ?? sourceCode.getFirstToken(node),
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astUtils.isCommaToken,
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);
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if (element) {
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continue;
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}
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context.report({
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node,
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loc: commaToken.loc,
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messageId: "unexpectedSparseArray",
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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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