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69 lines
2.0 KiB
Markdown
69 lines
2.0 KiB
Markdown
---
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title: With
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---
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## With
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JavaScript's `with` statement is a shorthand way to edit several properties on one object. Most developers discourage its usage, with best practice being not to use `with`. See Alternatives below for other approaches.
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**Note**: `"strict mode"` in ECMAScript 5 forbids usage of `with`.
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### Syntax
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```js
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with (expression)
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statement
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```
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### Example Usage
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In JavaScript, you can individually modify an object's properties as below:
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```javascript
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let earth = {};
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earth.moons = 1;
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earth.continents = 7;
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```
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`with` gives you a shorthand way to modify the properties on an object:
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```javascript
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with (earth) {
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moons = 1;
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continents = 7;
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}
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```
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While this example is contrived, you can understand cases of `with` better if you use larger objects as below:
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```javascript
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earth.continents.australia.geography.ocean = "Pacific";
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earth.continents.australia.geography.river = "Murray";
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earth.continents.australia.geography.mountain = "Kosciuszko";
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```
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### Alternatives
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You should not use `with`, as it has subtle bugs and compatibility issues. A highly recommended approach is to assign the object to a variable, and then to modify the variable's properties. Here is an example using a larger object:
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```javascript
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let earth = {
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continents: {
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australia: {
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geography: {}
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}
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}
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};
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let geo = earth.continents.australia.geography;
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geo.ocean = "Pacific";
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geo.river = "Murray";
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geo.mountain = "Kosciuszko";
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```
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### Try It Out
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https://repl.it/Mixg/5
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#### More Information:
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<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/with" target="_blank">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/with</a>
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<a href="https://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/" target="_blank">https://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/</a>
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<a href="http://2ality.com/2011/06/with-statement.html" target="_blank">http://2ality.com/2011/06/with-statement.html</a>
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