18 lines
1.2 KiB
Markdown
18 lines
1.2 KiB
Markdown
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---
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title: Boolean
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---
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## Boolean
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The Boolean object is an object wrapper for a boolean (true or false) value. You can explicitly define a Boolean as `new Boolean([value])`. The optional `value` argument is converted to a boolean value. If value is not specified, `0`, `-0`, `null`, `false`, `NaN`, `undefined`, or the empty string (`""`), the object is set to false. All other values, including any object or the string "false", create an object with a value of true. An interesting exception is when DOM's `document.all` is passed as an argument to the `Boolean` constructor, it is evaluated as `false`<sup>1</sup>.
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Boolean primitive value (`true` and `false` ) is not same as `Boolean` object values (`true` and `false`).
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#### More Information:
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<!-- Please add any articles you think might be helpful to read before writing the article -->
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[The Difference Between Boolean Objects and Boolean Primitives in JavaScript -- A Drip of JavaScript](http://adripofjavascript.com/blog/drips/the-difference-between-boolean-objects-and-boolean-primitives-in-javascript.html)
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### Sources
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1. [You Don't Know JavaScript, Chapter 4](https://github.com/getify/You-Dont-Know-JS/blob/master/types%20&%20grammar/ch4.md), line :364. Accessed on October 31, 2017.
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