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