Skip to content

Commit

Permalink
Correct a few usage of internal methods
Browse files Browse the repository at this point in the history
  • Loading branch information
@Josh-Cena
Josh-Cena committed Jul 18, 2022
1 parent ef59c2d commit 826c1e0
Show file tree
Hide file tree
Showing 3 changed files with 23 additions and 80 deletions.
95 changes: 19 additions & 76 deletions files/en-us/web/javascript/data_structures/index.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -155,79 +155,20 @@ In computer science, an object is a value in memory which is possibly referenced

In JavaScript, objects can be seen as a collection of properties. With the [object literal syntax](/en-US/docs/Web/JavaScript/Guide/Grammar_and_types#object_literals), a limited set of properties are initialized; then properties can be added and removed. Property values can be values of any type, including other objects, which enables building complex data structures. Properties are identified using _key_ values. A _key_ value is either a {{Glossary("String", "String value")}} or a {{Glossary("Symbol", "Symbol value")}}.

There are two types of object properties: The [_data_ property](#data_property) and the [_accessor_ property](#accessor_property).

> **Note:** Each property has corresponding *attributes*. Attributes are used internally by the JavaScript engine, so you cannot directly access them. That's why attributes are listed in double square brackets, rather than single.
>
> See {{jsxref("Object.defineProperty()")}} to learn more.
There are two types of object properties: The [_data_ property](#data_property) and the [_accessor_ property](#accessor_property). Each property has corresponding _attributes_. Each attribute is accessed internally by the JavaScript engine, but you can set them through {{jsxref("Object.defineProperty()")}}, or read them through {{jsxref("Object.getOwnPropertyDescriptor()")}}. You can read more about the various nuances on the {{jsxref("Object.defineProperty()")}} page.

#### Data property

Associates a key with a value, and has the following attributes:

<table class="standard-table">
<caption>
Attributes of a data property
</caption>
<thead>
<tr>
<th scope="col">Attribute</th>
<th scope="col">Type</th>
<th scope="col">Description</th>
<th scope="col">Default value</th>
</tr>
</thead>
<tbody>
<tr>
<td>[[Value]]</td>
<td>Any JavaScript type</td>
<td>The value retrieved by a get access of the property.</td>
<td><code>undefined</code></td>
</tr>
<tr>
<td>[[Writable]]</td>
<td>Boolean</td>
<td>
If <code>false</code>, the property's [[Value]] cannot be changed.
</td>
<td><code>false</code></td>
</tr>
<tr>
<td>[[Enumerable]]</td>
<td>Boolean</td>
<td>
<p>
If <code>true</code>, the property will be enumerated in
<a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...in"
><code>for...in</code></a
>
loops.<br />See also
<a
href="/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties"
>Enumerability and ownership of properties</a
>.
</p>
</td>
<td><code>false</code></td>
</tr>
<tr>
<td>[[Configurable]]</td>
<td>Boolean</td>
<td>
If <code>false</code>, the property cannot be deleted, cannot be changed
to an accessor property, and attributes other than [[Value]] and
[[Writable]] cannot be changed.
</td>
<td><code>false</code></td>
</tr>
</tbody>
</table>

| Attribute | Type | Description |
| ---------- | ------- | ----------------------------------------------------- |
| Read-only | Boolean | Reversed state of the ES5 [[Writable]] attribute. |
| DontEnum | Boolean | Reversed state of the ES5 [[Enumerable]] attribute. |
| DontDelete | Boolean | Reversed state of the ES5 [[Configurable]] attribute. |
Data properties associate a key with a value. It can be described by the following attributes:

- `value`
- : The value retrieved by a get access of the property. Can be any JavaScript value.
- `writable`
- : A boolean value indicating if the property can be changed with an assignment.
- `enumerable`
- : A boolean value indicating if the property can be enumerated by a [`for...in`](/en-US/docs/Web/JavaScript/Reference/Statements/for...in) loop. See also [Enumerability and ownership of properties](/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties) for how enumerability interacts with other functions and syntaxes.
- `configurable`
- : A boolean value indicating if the property can be deleted, can be changed to an accessor property, and can have its attributes changed.

#### Accessor property

Expand All @@ -237,12 +178,14 @@ Associates a key with one of two accessor functions (`get` and `set`) to retriev
An accessor property has the following attributes:

| Attribute | Type | Description | Default value |
| ---------------- | ------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------- |
| [[Get]] | Function object or `undefined` | The function is called with an empty argument list and retrieves the property value whenever a get access to the value is performed. See also [`get`](/en-US/docs/Web/JavaScript/Reference/Functions/get). | `undefined` |
| [[Set]] | Function object or `undefined` | The function is called with an argument that contains the assigned value and is executed whenever a specified property is attempted to be changed. See also [`set`](/en-US/docs/Web/JavaScript/Reference/Functions/set). | `undefined` |
| [[Enumerable]] | Boolean | If `true`, the property will be enumerated in [`for...in`](/en-US/docs/Web/JavaScript/Reference/Statements/for...in) loops. | `false` |
| [[Configurable]] | Boolean | If `false`, the property can't be deleted and can't be changed to a data property. | `false` |
- `get`
- : A function called with an empty argument list to retrieve the property value whenever a get access to the value is performed. See also [getters](/en-US/docs/Web/JavaScript/Reference/Functions/get). May be `undefined`.
- `set`
- : A function called with an argument that contains the assigned value. Executed whenever a specified property is attempted to be changed. See also [setters](/en-US/docs/Web/JavaScript/Reference/Functions/get). May be `undefined`.
- `enumerable`
- : A boolean value indicating if the property can be enumerated by a [`for...in`](/en-US/docs/Web/JavaScript/Reference/Statements/for...in) loop. See also [Enumerability and ownership of properties](/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties) for how enumerability interacts with other functions and syntaxes.
- `configurable`
- : A boolean value indicating if the property can be deleted, can be changed to an data property, and can have its attributes changed.

### "Normal" objects, and functions

Expand Down
4 changes: 2 additions & 2 deletions files/en-us/web/javascript/reference/global_objects/typedarray/from/index.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -94,8 +94,8 @@ Some subtle distinctions between {{jsxref("Array.from()")}} and
`TypedArray.from()` is not a constructor,
`TypedArray.from()` will throw a {{jsxref("TypeError")}},
where `Array.from()` defaults to creating a new {{jsxref("Array")}}.
- `TypedArray.from()` uses `[[Put]]` where
`Array.from()` uses `[[DefineProperty]]`. Hence, when
- `TypedArray.from()` uses `[[Set]]` where
`Array.from()` uses `[[DefineOwnProperty]]`. Hence, when
working with {{jsxref("Proxy")}} objects, it calls
{{jsxref("Global_Objects/Proxy/handler/set", "handler.set")}} to create new
elements rather than {{jsxref("Global_Objects/Proxy/handler/defineProperty",
Expand Down
4 changes: 2 additions & 2 deletions files/en-us/web/javascript/reference/global_objects/typedarray/of/index.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,8 +58,8 @@ Some subtle distinctions between {{jsxref("Array.of()")}} and
not a constructor, `TypedArray.of()` will throw a
{{jsxref("TypeError")}}, where `Array.of()` defaults to creating a new
{{jsxref("Array")}}.
- `TypedArray.of()` uses `[[Put]]` where
`Array.of()` uses `[[DefineProperty]]`. Hence, when working with
- `TypedArray.of()` uses `[[Set]]` where
`Array.of()` uses `[[DefineOwnProperty]]`. Hence, when working with
{{jsxref("Proxy")}} objects, it calls {{jsxref("Global_Objects/Proxy/handler/set",
"handler.set")}} to create new elements rather than
{{jsxref("Global_Objects/Proxy/handler/defineProperty", "handler.defineProperty()")}}.
Expand Down

0 comments on commit 826c1e0

Please sign in to comment.