145 lines
5 KiB
JavaScript
145 lines
5 KiB
JavaScript
/**
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* @fileoverview Rule to validate spacing before function paren.
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* @author Mathias Schreck <https://github.com/lo1tuma>
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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("../util/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 `function` definition opening parenthesis",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/space-before-function-paren"
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},
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fixable: "whitespace",
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schema: [
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{
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oneOf: [
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{
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enum: ["always", "never"]
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},
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{
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type: "object",
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properties: {
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anonymous: {
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enum: ["always", "never", "ignore"]
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},
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named: {
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enum: ["always", "never", "ignore"]
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},
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asyncArrow: {
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enum: ["always", "never", "ignore"]
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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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}
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]
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},
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create(context) {
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const sourceCode = context.getSourceCode();
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const baseConfig = typeof context.options[0] === "string" ? context.options[0] : "always";
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const overrideConfig = typeof context.options[0] === "object" ? context.options[0] : {};
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/**
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* Determines whether a function has a name.
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* @param {ASTNode} node The function node.
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* @returns {boolean} Whether the function has a name.
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*/
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function isNamedFunction(node) {
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if (node.id) {
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return true;
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}
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const parent = node.parent;
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return parent.type === "MethodDefinition" ||
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(parent.type === "Property" &&
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(
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parent.kind === "get" ||
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parent.kind === "set" ||
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parent.method
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)
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);
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}
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/**
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* Gets the config for a given function
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* @param {ASTNode} node The function node
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* @returns {string} "always", "never", or "ignore"
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*/
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function getConfigForFunction(node) {
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if (node.type === "ArrowFunctionExpression") {
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// Always ignore non-async functions and arrow functions without parens, e.g. async foo => bar
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if (node.async && astUtils.isOpeningParenToken(sourceCode.getFirstToken(node, { skip: 1 }))) {
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return overrideConfig.asyncArrow || baseConfig;
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}
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} else if (isNamedFunction(node)) {
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return overrideConfig.named || baseConfig;
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// `generator-star-spacing` should warn anonymous generators. E.g. `function* () {}`
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} else if (!node.generator) {
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return overrideConfig.anonymous || baseConfig;
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}
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return "ignore";
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}
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/**
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* Checks the parens of a function node
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* @param {ASTNode} node A function node
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* @returns {void}
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*/
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function checkFunction(node) {
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const functionConfig = getConfigForFunction(node);
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if (functionConfig === "ignore") {
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return;
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}
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const rightToken = sourceCode.getFirstToken(node, astUtils.isOpeningParenToken);
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const leftToken = sourceCode.getTokenBefore(rightToken);
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const hasSpacing = sourceCode.isSpaceBetweenTokens(leftToken, rightToken);
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if (hasSpacing && functionConfig === "never") {
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context.report({
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node,
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loc: leftToken.loc.end,
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message: "Unexpected space before function parentheses.",
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fix: fixer => fixer.removeRange([leftToken.range[1], rightToken.range[0]])
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});
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} else if (!hasSpacing && functionConfig === "always") {
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context.report({
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node,
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loc: leftToken.loc.end,
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message: "Missing space before function parentheses.",
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fix: fixer => fixer.insertTextAfter(leftToken, " ")
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});
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}
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}
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return {
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ArrowFunctionExpression: checkFunction,
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FunctionDeclaration: checkFunction,
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FunctionExpression: checkFunction
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};
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}
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};
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