'use strict';
// V8 has a fast path for `{ value, done }` literals, but it must be that order.
// https://source.chromium.org/chromium/chromium/src/+/main:v8/src/init/bootstrapper.cc;l=746-754;drc=e8ac4914ee6b24442aed773d3a041451692b6a9c
// Also, the ES spec technically requires that order.
// https://tc39.es/ecma262/multipage/abstract-operations.html#sec-createiterresultobject
const MESSAGE = 'Iterator result objects should place `value` before `done`.';
function getStaticPropertyName(property) {
const { key } = property;
if (!key) {
return;
}
if (key.type === 'Identifier' && !property.computed) {
return key.name;
}
if (key.type === 'Literal') {
return key.value;
}
}
module.exports = {
meta: {
type: 'suggestion',
fixable: 'code',
schema: [],
},
create(context) {
const sourceCode = context.sourceCode;
return {
ObjectExpression(node) {
let doneProperty;
let valueProperty;
for (const property of node.properties) {
if (property.type !== 'Property') {
continue;
}
switch (getStaticPropertyName(property)) {
case 'done':
doneProperty ??= property;
break;
case 'value':
valueProperty ??= property;
break;
}
}
if (doneProperty && valueProperty && doneProperty.range[0] < valueProperty.range[0]) {
context.report({
node: doneProperty,
message: MESSAGE,
fix(fixer) {
return [
fixer.replaceText(valueProperty, sourceCode.getText(doneProperty)),
fixer.replaceText(doneProperty, sourceCode.getText(valueProperty)),
];
},
});
}
},
};
},
};