45 lines
1.2 KiB
JavaScript
45 lines
1.2 KiB
JavaScript
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/**
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* @fileoverview Rule to flag comparisons to null without a type-checking
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* operator.
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* @author Ian Christian Myers
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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module.exports = {
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meta: {
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docs: {
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description: "disallow `null` comparisons without type-checking operators",
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category: "Best Practices",
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recommended: false,
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url: "https://eslint.org/docs/rules/no-eq-null"
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},
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schema: [],
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messages: {
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unexpected: "Use '===' to compare with null."
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}
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},
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create(context) {
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return {
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BinaryExpression(node) {
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const badOperator = node.operator === "==" || node.operator === "!=";
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if (node.right.type === "Literal" && node.right.raw === "null" && badOperator ||
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node.left.type === "Literal" && node.left.raw === "null" && badOperator) {
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context.report({ node, messageId: "unexpected" });
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}
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}
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};
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}
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};
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