Umama-at-Bluchip/Quick-UI

1/**2 * @fileoverview A rule to control the style of variable initializations.3 * @author Colin Ihrig4 */5 6"use strict";7 8//------------------------------------------------------------------------------9// Helpers10//------------------------------------------------------------------------------11 12/**13 * Checks whether or not a given node is a for loop.14 * @param {ASTNode} block A node to check.15 * @returns {boolean} `true` when the node is a for loop.16 */17function isForLoop(block) {18    return block.type === "ForInStatement" ||19    block.type === "ForOfStatement" ||20    block.type === "ForStatement";21}22 23/**24 * Checks whether or not a given declarator node has its initializer.25 * @param {ASTNode} node A declarator node to check.26 * @returns {boolean} `true` when the node has its initializer.27 */28function isInitialized(node) {29    const declaration = node.parent;30    const block = declaration.parent;31 32    if (isForLoop(block)) {33        if (block.type === "ForStatement") {34            return block.init === declaration;35        }36        return block.left === declaration;37    }38    return Boolean(node.init);39}40 41//------------------------------------------------------------------------------42// Rule Definition43//------------------------------------------------------------------------------44 45/** @type {import('../shared/types').Rule} */46module.exports = {47    meta: {48        type: "suggestion",49 50        docs: {51            description: "Require or disallow initialization in variable declarations",52            recommended: false,53            url: "https://eslint.org/docs/latest/rules/init-declarations"54        },55 56        schema: {57            anyOf: [58                {59                    type: "array",60                    items: [61                        {62                            enum: ["always"]63                        }64                    ],65                    minItems: 0,66                    maxItems: 167                },68                {69                    type: "array",70                    items: [71                        {72                            enum: ["never"]73                        },74                        {75                            type: "object",76                            properties: {77                                ignoreForLoopInit: {78                                    type: "boolean"79                                }80                            },81                            additionalProperties: false82                        }83                    ],84                    minItems: 0,85                    maxItems: 286                }87            ]88        },89        messages: {90            initialized: "Variable '{{idName}}' should be initialized on declaration.",91            notInitialized: "Variable '{{idName}}' should not be initialized on declaration."92        }93    },94 95    create(context) {96 97        const MODE_ALWAYS = "always",98            MODE_NEVER = "never";99 100        const mode = context.options[0] || MODE_ALWAYS;101        const params = context.options[1] || {};102 103        //--------------------------------------------------------------------------104        // Public API105        //--------------------------------------------------------------------------106 107        return {108            "VariableDeclaration:exit"(node) {109 110                const kind = node.kind,111                    declarations = node.declarations;112 113                for (let i = 0; i < declarations.length; ++i) {114                    const declaration = declarations[i],115                        id = declaration.id,116                        initialized = isInitialized(declaration),117                        isIgnoredForLoop = params.ignoreForLoopInit && isForLoop(node.parent);118                    let messageId = "";119 120                    if (mode === MODE_ALWAYS && !initialized) {121                        messageId = "initialized";122                    } else if (mode === MODE_NEVER && kind !== "const" && initialized && !isIgnoredForLoop) {123                        messageId = "notInitialized";124                    }125 126                    if (id.type === "Identifier" && messageId) {127                        context.report({128                            node: declaration,129                            messageId,130                            data: {131                                idName: id.name132                            }133                        });134                    }135                }136            }137        };138    }139};140