@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
261 lines (260 loc) • 11.2 kB
JavaScript
;
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Object.defineProperty(exports, "__esModule", { value: true });
const utils_1 = require("@typescript-eslint/utils");
const tsutils = __importStar(require("ts-api-utils"));
const ts = __importStar(require("typescript"));
const util_1 = require("../util");
exports.default = (0, util_1.createRule)({
name: 'no-misused-spread',
meta: {
type: 'problem',
docs: {
description: 'Disallow using the spread operator when it might cause unexpected behavior',
recommended: 'strict',
requiresTypeChecking: true,
},
hasSuggestions: true,
messages: {
addAwait: 'Add await operator.',
noArraySpreadInObject: 'Using the spread operator on an array in an object will result in a list of indices.',
noClassDeclarationSpreadInObject: 'Using the spread operator on class declarations will spread only their static properties, and will lose their class prototype.',
noClassInstanceSpreadInObject: 'Using the spread operator on class instances will lose their class prototype.',
noFunctionSpreadInObject: 'Using the spread operator on a function without additional properties can cause unexpected behavior. Did you forget to call the function?',
noIterableSpreadInObject: 'Using the spread operator on an Iterable in an object can cause unexpected behavior.',
noMapSpreadInObject: 'Using the spread operator on a Map in an object will result in an empty object. Did you mean to use `Object.fromEntries(map)` instead?',
noPromiseSpreadInObject: 'Using the spread operator on Promise in an object can cause unexpected behavior. Did you forget to await the promise?',
noStringSpread: [
'Using the spread operator on a string can mishandle special characters, as can `.split("")`.',
'- `...` produces Unicode code points, which will decompose complex emojis into individual emojis',
'- .split("") produces UTF-16 code units, which breaks rich characters in many languages',
'Consider using `Intl.Segmenter` for locale-aware string decomposition.',
"Otherwise, if you don't need to preserve emojis or other non-Ascii characters, disable this lint rule on this line or configure the 'allow' rule option.",
].join('\n'),
replaceMapSpreadInObject: 'Replace map spread in object with `Object.fromEntries()`',
},
schema: [
{
type: 'object',
additionalProperties: false,
properties: {
allow: {
...util_1.readonlynessOptionsSchema.properties.allow,
description: 'An array of type specifiers that are known to be safe to spread.',
},
},
},
],
},
defaultOptions: [
{
allow: [],
},
],
create(context, [options]) {
const services = (0, util_1.getParserServices)(context);
const checker = services.program.getTypeChecker();
function checkArrayOrCallSpread(node) {
const type = (0, util_1.getConstrainedTypeAtLocation)(services, node.argument);
if (!(0, util_1.typeMatchesSomeSpecifier)(type, options.allow, services.program) &&
isString(type)) {
context.report({
node,
messageId: 'noStringSpread',
});
}
}
function getMapSpreadSuggestions(node, type) {
const types = tsutils.unionTypeParts(type);
if (types.some(t => !isMap(services.program, t))) {
return null;
}
if (node.parent.type === utils_1.AST_NODE_TYPES.ObjectExpression &&
node.parent.properties.length === 1) {
return [
{
messageId: 'replaceMapSpreadInObject',
fix: (0, util_1.getWrappingFixer)({
node: node.parent,
innerNode: node.argument,
sourceCode: context.sourceCode,
wrap: code => `Object.fromEntries(${code})`,
}),
},
];
}
return [
{
messageId: 'replaceMapSpreadInObject',
fix: (0, util_1.getWrappingFixer)({
node: node.argument,
sourceCode: context.sourceCode,
wrap: code => `Object.fromEntries(${code})`,
}),
},
];
}
function getPromiseSpreadSuggestions(node) {
const isHighPrecendence = (0, util_1.isHigherPrecedenceThanAwait)(services.esTreeNodeToTSNodeMap.get(node));
return [
{
messageId: 'addAwait',
fix: fixer => isHighPrecendence
? fixer.insertTextBefore(node, 'await ')
: [
fixer.insertTextBefore(node, 'await ('),
fixer.insertTextAfter(node, ')'),
],
},
];
}
function checkObjectSpread(node) {
const type = (0, util_1.getConstrainedTypeAtLocation)(services, node.argument);
if ((0, util_1.typeMatchesSomeSpecifier)(type, options.allow, services.program)) {
return;
}
if (isPromise(services.program, type)) {
context.report({
node,
messageId: 'noPromiseSpreadInObject',
suggest: getPromiseSpreadSuggestions(node.argument),
});
return;
}
if (isFunctionWithoutProps(type)) {
context.report({
node,
messageId: 'noFunctionSpreadInObject',
});
return;
}
if (isMap(services.program, type)) {
context.report({
node,
messageId: 'noMapSpreadInObject',
suggest: getMapSpreadSuggestions(node, type),
});
return;
}
if (isArray(checker, type)) {
context.report({
node,
messageId: 'noArraySpreadInObject',
});
return;
}
if (isIterable(type, checker) &&
// Don't report when the type is string, since TS will flag it already
!isString(type)) {
context.report({
node,
messageId: 'noIterableSpreadInObject',
});
return;
}
if (isClassInstance(checker, type)) {
context.report({
node,
messageId: 'noClassInstanceSpreadInObject',
});
return;
}
if (isClassDeclaration(type)) {
context.report({
node,
messageId: 'noClassDeclarationSpreadInObject',
});
}
}
return {
'ArrayExpression > SpreadElement': checkArrayOrCallSpread,
'CallExpression > SpreadElement': checkArrayOrCallSpread,
JSXSpreadAttribute: checkObjectSpread,
'ObjectExpression > SpreadElement': checkObjectSpread,
};
},
});
function isIterable(type, checker) {
return tsutils
.typeParts(type)
.some(t => !!tsutils.getWellKnownSymbolPropertyOfType(t, 'iterator', checker));
}
function isArray(checker, type) {
return isTypeRecurser(type, t => checker.isArrayType(t) || checker.isTupleType(t));
}
function isString(type) {
return isTypeRecurser(type, t => (0, util_1.isTypeFlagSet)(t, ts.TypeFlags.StringLike));
}
function isFunctionWithoutProps(type) {
return isTypeRecurser(type, t => t.getCallSignatures().length > 0 && t.getProperties().length === 0);
}
function isPromise(program, type) {
return isTypeRecurser(type, t => (0, util_1.isPromiseLike)(program, t));
}
function isClassInstance(checker, type) {
return isTypeRecurser(type, t => {
// If the type itself has a construct signature, it's a class(-like)
if (t.getConstructSignatures().length) {
return false;
}
const symbol = t.getSymbol();
// If the type's symbol has a construct signature, the type is an instance
return !!symbol
?.getDeclarations()
?.some(declaration => checker
.getTypeOfSymbolAtLocation(symbol, declaration)
.getConstructSignatures().length);
});
}
function isClassDeclaration(type) {
return isTypeRecurser(type, t => {
if (tsutils.isObjectType(t) &&
tsutils.isObjectFlagSet(t, ts.ObjectFlags.InstantiationExpressionType)) {
return true;
}
const kind = t.getSymbol()?.valueDeclaration?.kind;
return (kind === ts.SyntaxKind.ClassDeclaration ||
kind === ts.SyntaxKind.ClassExpression);
});
}
function isMap(program, type) {
return isTypeRecurser(type, t => (0, util_1.isBuiltinSymbolLike)(program, t, ['Map', 'ReadonlyMap', 'WeakMap']));
}
function isTypeRecurser(type, predicate) {
if (type.isUnionOrIntersection()) {
return type.types.some(t => isTypeRecurser(t, predicate));
}
return predicate(type);
}