blob: 3c2fab7675beb445117e0e5d86748670f8483151 [file] [log] [blame] [edit]
/**
* Rule: prefer-await-to-then
* Discourage using then()/catch()/finally() and instead use async/await.
*/
'use strict'
const { getAncestors, getScope } = require('./lib/eslint-compat')
const getDocsUrl = require('./lib/get-docs-url')
module.exports = {
meta: {
type: 'suggestion',
docs: {
description:
'Prefer `await` to `then()`/`catch()`/`finally()` for reading Promise values.',
url: getDocsUrl('prefer-await-to-then'),
},
schema: [
{
type: 'object',
properties: {
strict: {
type: 'boolean',
},
},
},
],
messages: {
preferAwaitToCallback: 'Prefer await to then()/catch()/finally().',
},
},
create(context) {
/** Returns true if node is inside yield or await expression. */
function isInsideYieldOrAwait(node) {
return getAncestors(context, node).some((parent) => {
return (
parent.type === 'AwaitExpression' || parent.type === 'YieldExpression'
)
})
}
/**
* Returns true if node is created at the top-level scope.
* Await statements are not allowed at the top level,
* only within function declarations.
*/
function isTopLevelScoped(node) {
return getScope(context, node).block.type === 'Program'
}
const { strict } = context.options[0] || {}
return {
'CallExpression > MemberExpression.callee'(node) {
if (isTopLevelScoped(node) || (!strict && isInsideYieldOrAwait(node))) {
return
}
// if you're a then/catch/finally expression then you're probably a promise
if (
node.property &&
(node.property.name === 'then' ||
node.property.name === 'catch' ||
node.property.name === 'finally')
) {
context.report({
node: node.property,
messageId: 'preferAwaitToCallback',
})
}
},
}
},
}