time-to-botec

Benchmark sampling in different programming languages
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README.md (4114B)

      1 <!--
      2 
      3 @license Apache-2.0
      4 
      5 Copyright (c) 2018 The Stdlib Authors.
      6 
      7 Licensed under the Apache License, Version 2.0 (the "License");
      8 you may not use this file except in compliance with the License.
      9 You may obtain a copy of the License at
     10 
     11    http://www.apache.org/licenses/LICENSE-2.0
     12 
     13 Unless required by applicable law or agreed to in writing, software
     14 distributed under the License is distributed on an "AS IS" BASIS,
     15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     16 See the License for the specific language governing permissions and
     17 limitations under the License.
     18 
     19 -->
     20 
     21 # Define Properties
     22 
     23 > [Define][mdn-define-properties] (and/or modify) object properties.
     24 
     25 <section class="usage">
     26 
     27 ## Usage
     28 
     29 ```javascript
     30 var defineProperties = require( '@stdlib/utils/define-properties' );
     31 ```
     32 
     33 #### defineProperties( obj, properties )
     34 
     35 [Defines][mdn-define-properties] (and/or modifies) object properties.
     36 
     37 ```javascript
     38 var objectKeys = require( '@stdlib/utils/keys' );
     39 
     40 var obj = {};
     41 defineProperties( obj, {
     42     'foo': {
     43         'value': 'bar',
     44         'writable': false,
     45         'configurable': false,
     46         'enumerable': true
     47     },
     48     'baz': {
     49         'value': 13,
     50         'enumerable': false
     51     }
     52 });
     53 
     54 // Retrieve all enumerable keys:
     55 var keys = objectKeys( obj );
     56 // returns [...]
     57 ```
     58 
     59 The `properties` parameter is an `object` whose own enumerable property values are descriptors for the properties to be defined or modified. A property descriptor has the following optional properties:
     60 
     61 -   **configurable**: `boolean` indicating if property descriptor can be changed and if the property can be deleted from the provided object. Default: `false`.
     62 -   **enumerable**: `boolean` indicating if the property shows up when enumerating object properties. Default: `false`.
     63 -   **writable**: `boolean` indicating if the value associated with the property can be changed with an assignment operator. Default: `false`.
     64 -   **value**: property value.
     65 -   **get**: `function` which serves as a getter for the property, or, if no getter, `undefined`. When the property is accessed, a getter function is called without arguments and with the `this` context set to the object through which the property is accessed (which may not be the object on which the property is defined due to inheritance). The return value will be used as the property value. Default: `undefined`.
     66 -   **set**: `function` which serves as a setter for the property, or, if no setter, `undefined`. When assigning a property value, a setter function is called with one argument (the value being assigned to the property) and with the `this` context set to the object through which the property is assigned. Default: `undefined`.
     67 
     68 </section>
     69 
     70 <!-- /.usage -->
     71 
     72 <section class="notes">
     73 
     74 ## Notes
     75 
     76 -   Property descriptors come in two flavors: **data descriptors** and **accessor descriptors**. A data descriptor is a property that has a value, which may or may not be writable. An accessor descriptor is a property described by a getter-setter function pair. A descriptor must be **one** of these two flavors and **cannot** be both.
     77 
     78 </section>
     79 
     80 <!-- /.notes -->
     81 
     82 <section class="examples">
     83 
     84 ## Examples
     85 
     86 <!-- eslint no-undef: "error", no-restricted-syntax: "off" -->
     87 
     88 ```javascript
     89 var defineProperties = require( '@stdlib/utils/define-properties' );
     90 
     91 function Person( name ) {
     92     if ( !(this instanceof Person) ) {
     93         return new Person( name );
     94     }
     95     defineProperties( this, {
     96         'name': {
     97             'value': name,
     98             'writable': false
     99         },
    100         'greeting': {
    101             'get': function greet() {
    102                 return 'Hello '+this.name;
    103             }
    104         }
    105     });
    106     return this;
    107 }
    108 
    109 var person = new Person( 'Simon' );
    110 
    111 try {
    112     person.name = 'Peter';
    113 } catch ( err ) {
    114     console.log( err.message );
    115 }
    116 
    117 var greeting = person.greeting;
    118 // returns <string>
    119 ```
    120 
    121 </section>
    122 
    123 <!-- /.examples -->
    124 
    125 <section class="links">
    126 
    127 [mdn-define-properties]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperties
    128 
    129 </section>
    130 
    131 <!-- /.links -->