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35 lines
1.3 KiB
HTML
35 lines
1.3 KiB
HTML
<template name="pkg_underscore">
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{{#markdown}}
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## `underscore`
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[Underscore](http://underscorejs.org/) is a utility-belt library for
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JavaScript that provides support for functional programming. It is
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invaluable for writing clear, concise JavaScript in a functional style.
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The `underscore` package defines the `_` namespace on both the client
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and the server.
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{{#warning}}
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Currently, underscore is included in all projects, as the Meteor
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core depends on it. _ is available in the global namespace on both the
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client and the server even if you do not include this package. However
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if you do use underscore in your application, you should still add the
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package as we will remove the default underscore in the future.
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{{/warning}}
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{{#warning}}
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We have slightly modified the way Underscore differentiates between
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objects and arrays in [collection functions](http://underscorejs.org/#each).
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The original Underscore logic is to treat any object with a numeric `length`
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property as an array (which helps it work properly on
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[`NodeList`s](https://developer.mozilla.org/en-US/docs/Web/API/NodeList)).
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In Meteor's version of Underscore, objects with a numeric `length` property
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are treated as objects if they have no prototype (specifically, if
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`x.constructor === Object`.
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{{/warning}}
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{{/markdown}}
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</template>
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