+++ /dev/null
-/**
- * @fileoverview Prefers object spread property over Object.assign
- * @author Sharmila Jesupaul
- * See LICENSE file in root directory for full license.
- */
-
-"use strict";
-
-const { CALL, ReferenceTracker } = require("eslint-utils");
-const {
- isCommaToken,
- isOpeningParenToken,
- isClosingParenToken,
- isParenthesised
-} = require("./utils/ast-utils");
-
-const ANY_SPACE = /\s/u;
-
-/**
- * Helper that checks if the Object.assign call has array spread
- * @param {ASTNode} node The node that the rule warns on
- * @returns {boolean} - Returns true if the Object.assign call has array spread
- */
-function hasArraySpread(node) {
- return node.arguments.some(arg => arg.type === "SpreadElement");
-}
-
-/**
- * Helper that checks if the node needs parentheses to be valid JS.
- * The default is to wrap the node in parentheses to avoid parsing errors.
- * @param {ASTNode} node The node that the rule warns on
- * @param {Object} sourceCode in context sourcecode object
- * @returns {boolean} - Returns true if the node needs parentheses
- */
-function needsParens(node, sourceCode) {
- const parent = node.parent;
-
- switch (parent.type) {
- case "VariableDeclarator":
- case "ArrayExpression":
- case "ReturnStatement":
- case "CallExpression":
- case "Property":
- return false;
- case "AssignmentExpression":
- return parent.left === node && !isParenthesised(sourceCode, node);
- default:
- return !isParenthesised(sourceCode, node);
- }
-}
-
-/**
- * Determines if an argument needs parentheses. The default is to not add parens.
- * @param {ASTNode} node The node to be checked.
- * @param {Object} sourceCode in context sourcecode object
- * @returns {boolean} True if the node needs parentheses
- */
-function argNeedsParens(node, sourceCode) {
- switch (node.type) {
- case "AssignmentExpression":
- case "ArrowFunctionExpression":
- case "ConditionalExpression":
- return !isParenthesised(sourceCode, node);
- default:
- return false;
- }
-}
-
-/**
- * Get the parenthesis tokens of a given ObjectExpression node.
- * This incldues the braces of the object literal and enclosing parentheses.
- * @param {ASTNode} node The node to get.
- * @param {Token} leftArgumentListParen The opening paren token of the argument list.
- * @param {SourceCode} sourceCode The source code object to get tokens.
- * @returns {Token[]} The parenthesis tokens of the node. This is sorted by the location.
- */
-function getParenTokens(node, leftArgumentListParen, sourceCode) {
- const parens = [sourceCode.getFirstToken(node), sourceCode.getLastToken(node)];
- let leftNext = sourceCode.getTokenBefore(node);
- let rightNext = sourceCode.getTokenAfter(node);
-
- // Note: don't include the parens of the argument list.
- while (
- leftNext &&
- rightNext &&
- leftNext.range[0] > leftArgumentListParen.range[0] &&
- isOpeningParenToken(leftNext) &&
- isClosingParenToken(rightNext)
- ) {
- parens.push(leftNext, rightNext);
- leftNext = sourceCode.getTokenBefore(leftNext);
- rightNext = sourceCode.getTokenAfter(rightNext);
- }
-
- return parens.sort((a, b) => a.range[0] - b.range[0]);
-}
-
-/**
- * Get the range of a given token and around whitespaces.
- * @param {Token} token The token to get range.
- * @param {SourceCode} sourceCode The source code object to get tokens.
- * @returns {number} The end of the range of the token and around whitespaces.
- */
-function getStartWithSpaces(token, sourceCode) {
- const text = sourceCode.text;
- let start = token.range[0];
-
- // If the previous token is a line comment then skip this step to avoid commenting this token out.
- {
- const prevToken = sourceCode.getTokenBefore(token, { includeComments: true });
-
- if (prevToken && prevToken.type === "Line") {
- return start;
- }
- }
-
- // Detect spaces before the token.
- while (ANY_SPACE.test(text[start - 1] || "")) {
- start -= 1;
- }
-
- return start;
-}
-
-/**
- * Get the range of a given token and around whitespaces.
- * @param {Token} token The token to get range.
- * @param {SourceCode} sourceCode The source code object to get tokens.
- * @returns {number} The start of the range of the token and around whitespaces.
- */
-function getEndWithSpaces(token, sourceCode) {
- const text = sourceCode.text;
- let end = token.range[1];
-
- // Detect spaces after the token.
- while (ANY_SPACE.test(text[end] || "")) {
- end += 1;
- }
-
- return end;
-}
-
-/**
- * Autofixes the Object.assign call to use an object spread instead.
- * @param {ASTNode|null} node The node that the rule warns on, i.e. the Object.assign call
- * @param {string} sourceCode sourceCode of the Object.assign call
- * @returns {Function} autofixer - replaces the Object.assign with a spread object.
- */
-function defineFixer(node, sourceCode) {
- return function *(fixer) {
- const leftParen = sourceCode.getTokenAfter(node.callee, isOpeningParenToken);
- const rightParen = sourceCode.getLastToken(node);
-
- // Remove the callee `Object.assign`
- yield fixer.remove(node.callee);
-
- // Replace the parens of argument list to braces.
- if (needsParens(node, sourceCode)) {
- yield fixer.replaceText(leftParen, "({");
- yield fixer.replaceText(rightParen, "})");
- } else {
- yield fixer.replaceText(leftParen, "{");
- yield fixer.replaceText(rightParen, "}");
- }
-
- // Process arguments.
- for (const argNode of node.arguments) {
- const innerParens = getParenTokens(argNode, leftParen, sourceCode);
- const left = innerParens.shift();
- const right = innerParens.pop();
-
- if (argNode.type === "ObjectExpression") {
- const maybeTrailingComma = sourceCode.getLastToken(argNode, 1);
- const maybeArgumentComma = sourceCode.getTokenAfter(right);
-
- /*
- * Make bare this object literal.
- * And remove spaces inside of the braces for better formatting.
- */
- for (const innerParen of innerParens) {
- yield fixer.remove(innerParen);
- }
- const leftRange = [left.range[0], getEndWithSpaces(left, sourceCode)];
- const rightRange = [
- Math.max(getStartWithSpaces(right, sourceCode), leftRange[1]), // Ensure ranges don't overlap
- right.range[1]
- ];
-
- yield fixer.removeRange(leftRange);
- yield fixer.removeRange(rightRange);
-
- // Remove the comma of this argument if it's duplication.
- if (
- (argNode.properties.length === 0 || isCommaToken(maybeTrailingComma)) &&
- isCommaToken(maybeArgumentComma)
- ) {
- yield fixer.remove(maybeArgumentComma);
- }
- } else {
-
- // Make spread.
- if (argNeedsParens(argNode, sourceCode)) {
- yield fixer.insertTextBefore(left, "...(");
- yield fixer.insertTextAfter(right, ")");
- } else {
- yield fixer.insertTextBefore(left, "...");
- }
- }
- }
- };
-}
-
-module.exports = {
- meta: {
- type: "suggestion",
-
- docs: {
- description:
- "disallow using Object.assign with an object literal as the first argument and prefer the use of object spread instead.",
- category: "Stylistic Issues",
- recommended: false,
- url: "https://eslint.org/docs/rules/prefer-object-spread"
- },
-
- schema: [],
- fixable: "code",
-
- messages: {
- useSpreadMessage: "Use an object spread instead of `Object.assign` eg: `{ ...foo }`.",
- useLiteralMessage: "Use an object literal instead of `Object.assign`. eg: `{ foo: bar }`."
- }
- },
-
- create(context) {
- const sourceCode = context.getSourceCode();
-
- return {
- Program() {
- const scope = context.getScope();
- const tracker = new ReferenceTracker(scope);
- const trackMap = {
- Object: {
- assign: { [CALL]: true }
- }
- };
-
- // Iterate all calls of `Object.assign` (only of the global variable `Object`).
- for (const { node } of tracker.iterateGlobalReferences(trackMap)) {
- if (
- node.arguments.length >= 1 &&
- node.arguments[0].type === "ObjectExpression" &&
- !hasArraySpread(node)
- ) {
- const messageId = node.arguments.length === 1
- ? "useLiteralMessage"
- : "useSpreadMessage";
- const fix = defineFixer(node, sourceCode);
-
- context.report({ node, messageId, fix });
- }
- }
- }
- };
- }
-};
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