108 lines
2.6 KiB
JavaScript
108 lines
2.6 KiB
JavaScript
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'use strict';
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const {
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addParenthesizesToReturnOrThrowExpression,
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removeSpacesAfter,
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} = require('./fix/index.js');
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const {isParenthesized} = require('./utils/parentheses.js');
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const needsSemicolon = require('./utils/needs-semicolon.js');
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const isOnSameLine = require('./utils/is-on-same-line.js');
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const MESSAGE_ID = 'no-unnecessary-await';
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const messages = {
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[MESSAGE_ID]: 'Do not `await` non-promise value.',
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};
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function notPromise(node) {
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switch (node.type) {
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case 'ArrayExpression':
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case 'ArrowFunctionExpression':
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case 'AwaitExpression':
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case 'BinaryExpression':
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case 'ClassExpression':
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case 'FunctionExpression':
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case 'JSXElement':
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case 'JSXFragment':
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case 'Literal':
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case 'TemplateLiteral':
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case 'UnaryExpression':
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case 'UpdateExpression': {
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return true;
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}
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case 'SequenceExpression': {
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return notPromise(node.expressions[node.expressions.length - 1]);
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}
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// No default
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}
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return false;
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}
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/** @param {import('eslint').Rule.RuleContext} context */
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const create = context => ({
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AwaitExpression(node) {
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if (!notPromise(node.argument)) {
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return;
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}
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const sourceCode = context.getSourceCode();
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const awaitToken = sourceCode.getFirstToken(node);
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const problem = {
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node,
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loc: awaitToken.loc,
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messageId: MESSAGE_ID,
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};
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const valueNode = node.argument;
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if (
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// Removing `await` may change them to a declaration, if there is no `id` will cause SyntaxError
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valueNode.type === 'FunctionExpression'
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|| valueNode.type === 'ClassExpression'
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// `+await +1` -> `++1`
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|| (
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node.parent.type === 'UnaryExpression'
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&& valueNode.type === 'UnaryExpression'
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&& node.parent.operator === valueNode.operator
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)
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) {
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return problem;
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}
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return Object.assign(problem, {
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/** @param {import('eslint').Rule.RuleFixer} fixer */
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* fix(fixer) {
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if (
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!isOnSameLine(awaitToken, valueNode)
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&& !isParenthesized(node, sourceCode)
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) {
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yield * addParenthesizesToReturnOrThrowExpression(fixer, node.parent, sourceCode);
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}
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yield fixer.remove(awaitToken);
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yield removeSpacesAfter(awaitToken, sourceCode, fixer);
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const nextToken = sourceCode.getTokenAfter(awaitToken);
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const tokenBefore = sourceCode.getTokenBefore(awaitToken);
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if (needsSemicolon(tokenBefore, sourceCode, nextToken.value)) {
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yield fixer.insertTextBefore(nextToken, ';');
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}
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},
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});
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},
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});
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/** @type {import('eslint').Rule.RuleModule} */
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module.exports = {
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create,
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meta: {
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type: 'suggestion',
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docs: {
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description: 'Disallow awaiting non-promise values.',
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},
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fixable: 'code',
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messages,
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},
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};
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