| /** |
| * @fileoverview Rule to define spacing before/after arrow function's arrow. |
| * @author Jxck |
| */ |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Requirements |
| //------------------------------------------------------------------------------ |
| |
| const astUtils = require("./utils/ast-utils"); |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "layout", |
| |
| docs: { |
| description: "enforce consistent spacing before and after the arrow in arrow functions", |
| category: "ECMAScript 6", |
| recommended: false, |
| url: "https://eslint.org/docs/rules/arrow-spacing" |
| }, |
| |
| fixable: "whitespace", |
| |
| schema: [ |
| { |
| type: "object", |
| properties: { |
| before: { |
| type: "boolean", |
| default: true |
| }, |
| after: { |
| type: "boolean", |
| default: true |
| } |
| }, |
| additionalProperties: false |
| } |
| ], |
| |
| messages: { |
| expectedBefore: "Missing space before =>.", |
| unexpectedBefore: "Unexpected space before =>.", |
| |
| expectedAfter: "Missing space after =>.", |
| unexpectedAfter: "Unexpected space after =>." |
| } |
| }, |
| |
| create(context) { |
| |
| // merge rules with default |
| const rule = Object.assign({}, context.options[0]); |
| |
| rule.before = rule.before !== false; |
| rule.after = rule.after !== false; |
| |
| const sourceCode = context.getSourceCode(); |
| |
| /** |
| * Get tokens of arrow(`=>`) and before/after arrow. |
| * @param {ASTNode} node The arrow function node. |
| * @returns {Object} Tokens of arrow and before/after arrow. |
| */ |
| function getTokens(node) { |
| const arrow = sourceCode.getTokenBefore(node.body, astUtils.isArrowToken); |
| |
| return { |
| before: sourceCode.getTokenBefore(arrow), |
| arrow, |
| after: sourceCode.getTokenAfter(arrow) |
| }; |
| } |
| |
| /** |
| * Count spaces before/after arrow(`=>`) token. |
| * @param {Object} tokens Tokens before/after arrow. |
| * @returns {Object} count of space before/after arrow. |
| */ |
| function countSpaces(tokens) { |
| const before = tokens.arrow.range[0] - tokens.before.range[1]; |
| const after = tokens.after.range[0] - tokens.arrow.range[1]; |
| |
| return { before, after }; |
| } |
| |
| /** |
| * Determines whether space(s) before after arrow(`=>`) is satisfy rule. |
| * if before/after value is `true`, there should be space(s). |
| * if before/after value is `false`, there should be no space. |
| * @param {ASTNode} node The arrow function node. |
| * @returns {void} |
| */ |
| function spaces(node) { |
| const tokens = getTokens(node); |
| const countSpace = countSpaces(tokens); |
| |
| if (rule.before) { |
| |
| // should be space(s) before arrow |
| if (countSpace.before === 0) { |
| context.report({ |
| node: tokens.before, |
| messageId: "expectedBefore", |
| fix(fixer) { |
| return fixer.insertTextBefore(tokens.arrow, " "); |
| } |
| }); |
| } |
| } else { |
| |
| // should be no space before arrow |
| if (countSpace.before > 0) { |
| context.report({ |
| node: tokens.before, |
| messageId: "unexpectedBefore", |
| fix(fixer) { |
| return fixer.removeRange([tokens.before.range[1], tokens.arrow.range[0]]); |
| } |
| }); |
| } |
| } |
| |
| if (rule.after) { |
| |
| // should be space(s) after arrow |
| if (countSpace.after === 0) { |
| context.report({ |
| node: tokens.after, |
| messageId: "expectedAfter", |
| fix(fixer) { |
| return fixer.insertTextAfter(tokens.arrow, " "); |
| } |
| }); |
| } |
| } else { |
| |
| // should be no space after arrow |
| if (countSpace.after > 0) { |
| context.report({ |
| node: tokens.after, |
| messageId: "unexpectedAfter", |
| fix(fixer) { |
| return fixer.removeRange([tokens.arrow.range[1], tokens.after.range[0]]); |
| } |
| }); |
| } |
| } |
| } |
| |
| return { |
| ArrowFunctionExpression: spaces |
| }; |
| } |
| }; |