Keen Yee Liau fd51e01335 fix(compiler): Metadata should not include methods on Object.prototype (#38292)
This commit fixes a bug in View Engine whereby the compiler errorneously
thinks that a method of a component has decorator metadata when that
method is one of those in `Object.prototype`, for example `toString`.

This bug is discovered in v10.0.4 of `@angular/language-service` after
the default bundle format was switched from ES5 to ES2015.

ES5 output:
```js
if (propMetadata[propName]) {
    decorators.push.apply(decorators, __spread(propMetadata[propName]));
}
```

ES2015 output:
```js
if (propMetadata[propName]) {
    decorators.push(...propMetadata[propName]);
}
```

The bug was not discovered in ES5 because the polyfill for the spread
operator happily accepts parameters that do not have the `iterable`
symbol:

```js
function __spread() {
    for (var ar = [], i = 0; i < arguments.length; i++)
        ar = ar.concat(__read(arguments[i]));
    return ar;
}
```

whereas in es2015 it’ll fail since the iterable symbol is not present in
`propMetadata['toString']` which evaluates to a function.

Fixes https://github.com/angular/vscode-ng-language-service/issues/859

PR Close #38292
2020-07-30 15:18:28 -07:00
..
2020-01-13 07:21:43 -08:00

Angular

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Usage information and reference details can be found in Angular documentation.

License: MIT