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denoland-deno/std/_util/has_own_property.ts
2021-01-10 21:59:07 -05:00

30 lines
950 B
TypeScript

// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
/**
* Determines whether an object has a property with the specified name.
* Avoid calling prototype builtin `hasOwnProperty` for two reasons:
*
* 1. `hasOwnProperty` is defined on the object as something else:
*
* const options = {
* ending: 'utf8',
* hasOwnProperty: 'foo'
* };
* options.hasOwnProperty('ending') // throws a TypeError
*
* 2. The object doesn't inherit from `Object.prototype`:
*
* const options = Object.create(null);
* options.ending = 'utf8';
* options.hasOwnProperty('ending'); // throws a TypeError
*
* @param obj A Object.
* @param v A property name.
* @see https://eslint.org/docs/rules/no-prototype-builtins
*/
export function hasOwnProperty<T>(obj: T, v: PropertyKey): boolean {
if (obj == null) {
return false;
}
return Object.prototype.hasOwnProperty.call(obj, v);
}