171 lines
4.3 KiB
JavaScript
171 lines
4.3 KiB
JavaScript
/**
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* @fileoverview A rule to control the style of variable initializations.
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* @author Colin Ihrig
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*/
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'use strict';
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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/**
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* Checks whether or not a given node is a for loop.
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* @param {ASTNode} block A node to check.
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* @returns {boolean} `true` when the node is a for loop.
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*/
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function isForLoop(block) {
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return (
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block.type === 'ForInStatement' ||
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block.type === 'ForOfStatement' ||
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block.type === 'ForStatement'
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);
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}
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/**
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* Checks whether or not a given declarator node has its initializer.
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* @param {ASTNode} node A declarator node to check.
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* @returns {boolean} `true` when the node has its initializer.
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*/
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function isInitialized(node) {
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const declaration = node.parent;
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const block = declaration.parent;
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if (isForLoop(block)) {
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if (block.type === 'ForStatement') {
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return block.init === declaration;
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}
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return block.left === declaration;
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}
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return Boolean(node.init);
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}
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../types').Rule.RuleModule} */
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module.exports = {
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meta: {
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type: 'suggestion',
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dialects: ['typescript', 'javascript'],
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language: 'javascript',
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docs: {
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description:
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'Require or disallow initialization in variable declarations',
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recommended: false,
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frozen: true,
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url: 'https://eslint.org/docs/latest/rules/init-declarations',
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},
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schema: {
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anyOf: [
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{
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type: 'array',
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items: [
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{
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enum: ['always'],
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},
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],
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minItems: 0,
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maxItems: 1,
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},
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{
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type: 'array',
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items: [
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{
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enum: ['never'],
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},
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{
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type: 'object',
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properties: {
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ignoreForLoopInit: {
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type: 'boolean',
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},
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},
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additionalProperties: false,
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},
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],
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minItems: 0,
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maxItems: 2,
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},
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],
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},
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messages: {
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initialized:
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"Variable '{{idName}}' should be initialized on declaration.",
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notInitialized:
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"Variable '{{idName}}' should not be initialized on declaration.",
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},
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},
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create(context) {
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const MODE_ALWAYS = 'always',
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MODE_NEVER = 'never';
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const mode = context.options[0] || MODE_ALWAYS;
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const params = context.options[1] || {};
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// Track whether we're inside a declared namespace
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let insideDeclaredNamespace = false;
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//--------------------------------------------------------------------------
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// Public API
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//--------------------------------------------------------------------------
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return {
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TSModuleDeclaration(node) {
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if (node.declare) {
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insideDeclaredNamespace = true;
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}
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},
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'TSModuleDeclaration:exit'(node) {
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if (node.declare) {
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insideDeclaredNamespace = false;
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}
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},
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'VariableDeclaration:exit'(node) {
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const kind = node.kind,
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declarations = node.declarations;
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if (node.declare || insideDeclaredNamespace) {
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return;
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}
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for (let i = 0; i < declarations.length; ++i) {
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const declaration = declarations[i],
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id = declaration.id,
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initialized = isInitialized(declaration),
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isIgnoredForLoop =
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params.ignoreForLoopInit && isForLoop(node.parent);
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let messageId = '';
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if (mode === MODE_ALWAYS && !initialized) {
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messageId = 'initialized';
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} else if (
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mode === MODE_NEVER &&
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kind !== 'const' &&
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initialized &&
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!isIgnoredForLoop
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) {
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messageId = 'notInitialized';
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}
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if (id.type === 'Identifier' && messageId) {
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context.report({
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node: declaration,
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messageId,
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data: {
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idName: id.name,
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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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};
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