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Frontend-Learner/node_modules/eslint-plugin-unicorn/rules/no-new-array.js

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+import {isParenthesized, getStaticValue} from '@eslint-community/eslint-utils';
+import needsSemicolon from './utils/needs-semicolon.js';
+import isNumber from './utils/is-number.js';
+import {isNewExpression} from './ast/index.js';
+
+const MESSAGE_ID_ERROR = 'error';
+const MESSAGE_ID_LENGTH = 'array-length';
+const MESSAGE_ID_ONLY_ELEMENT = 'only-element';
+const MESSAGE_ID_SPREAD = 'spread';
+const messages = {
+	[MESSAGE_ID_ERROR]: '`new Array()` is unclear in intent; use either `[x]` or `Array.from({length: x})`',
+	[MESSAGE_ID_LENGTH]: 'The argument is the length of array.',
+	[MESSAGE_ID_ONLY_ELEMENT]: 'The argument is the only element of array.',
+	[MESSAGE_ID_SPREAD]: 'Spread the argument.',
+};
+
+function getProblem(context, node) {
+	if (
+		!isNewExpression(node, {
+			name: 'Array',
+			argumentsLength: 1,
+			allowSpreadElement: true,
+		})
+	) {
+		return;
+	}
+
+	const problem = {
+		node,
+		messageId: MESSAGE_ID_ERROR,
+	};
+
+	const [argumentNode] = node.arguments;
+
+	const {sourceCode} = context;
+	let text = sourceCode.getText(argumentNode);
+	if (isParenthesized(argumentNode, sourceCode)) {
+		text = `(${text})`;
+	}
+
+	const maybeSemiColon = needsSemicolon(sourceCode.getTokenBefore(node), context, '[')
+		? ';'
+		: '';
+
+	// We are not sure how many `arguments` passed
+	if (argumentNode.type === 'SpreadElement') {
+		problem.suggest = [
+			{
+				messageId: MESSAGE_ID_SPREAD,
+				fix: fixer => fixer.replaceText(node, `${maybeSemiColon}[${text}]`),
+			},
+		];
+		return problem;
+	}
+
+	const fromLengthText = `Array.from(${text === 'length' ? '{length}' : `{length: ${text}}`})`;
+	const scope = sourceCode.getScope(node);
+	if (isNumber(argumentNode, scope)) {
+		problem.fix = fixer => fixer.replaceText(node, fromLengthText);
+		return problem;
+	}
+
+	const onlyElementText = `${maybeSemiColon}[${text}]`;
+	const result = getStaticValue(argumentNode, scope);
+	if (result !== null && typeof result.value !== 'number') {
+		problem.fix = fixer => fixer.replaceText(node, onlyElementText);
+		return problem;
+	}
+
+	// We don't know the argument is number or not
+	problem.suggest = [
+		{
+			messageId: MESSAGE_ID_LENGTH,
+			fix: fixer => fixer.replaceText(node, fromLengthText),
+		},
+		{
+			messageId: MESSAGE_ID_ONLY_ELEMENT,
+			fix: fixer => fixer.replaceText(node, onlyElementText),
+		},
+	];
+	return problem;
+}
+
+/** @param {import('eslint').Rule.RuleContext} context */
+const create = context => ({
+	NewExpression(node) {
+		return getProblem(context, node);
+	},
+});
+
+/** @type {import('eslint').Rule.RuleModule} */
+const config = {
+	create,
+	meta: {
+		type: 'suggestion',
+		docs: {
+			description: 'Disallow `new Array()`.',
+			recommended: 'unopinionated',
+		},
+		fixable: 'code',
+		hasSuggestions: true,
+		messages,
+	},
+};
+
+export default config;