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diff --git a/bin/wiki/ImportarDesdeURL/node_modules/css-select/README.md b/bin/wiki/ImportarDesdeURL/node_modules/css-select/README.md new file mode 100644 index 00000000..e36282fe --- /dev/null +++ b/bin/wiki/ImportarDesdeURL/node_modules/css-select/README.md @@ -0,0 +1,133 @@ +# css-select [](https://npmjs.org/package/css-select) [](http://travis-ci.org/fb55/css-select) [](https://npmjs.org/package/css-select) [](https://coveralls.io/r/fb55/css-select) + +a CSS selector compiler/engine + +## What? + +css-select turns CSS selectors into functions that tests if elements match them. When searching for elements, testing is executed "from the top", similar to how browsers execute CSS selectors. + +In its default configuration, css-select queries the DOM structure of the [`domhandler`](https://github.com/fb55/domhandler) module (also known as htmlparser2 DOM). + +__Features:__ + +- Full implementation of CSS3 selectors +- Partial implementation of jQuery/Sizzle extensions +- Very high test coverage +- Pretty good performance + +## Why? + +The traditional approach of executing CSS selectors, named left-to-right execution, is to execute every component of the selector in order, from left to right _(duh)_. The execution of the selector `a b` for example will first query for `a` elements, then search these for `b` elements. (That's the approach of eg. [`Sizzle`](https://github.com/jquery/sizzle), [`nwmatcher`](https://github.com/dperini/nwmatcher/) and [`qwery`](https://github.com/ded/qwery).) + +While this works, it has some downsides: Children of `a`s will be checked multiple times; first, to check if they are also `a`s, then, for every superior `a` once, if they are `b`s. Using [Big O notation](http://en.wikipedia.org/wiki/Big_O_notation), that would be `O(n^(k+1))`, where `k` is the number of descendant selectors (that's the space in the example above). + +The far more efficient approach is to first look for `b` elements, then check if they have superior `a` elements: Using big O notation again, that would be `O(n)`. That's called right-to-left execution. + +And that's what css-select does – and why it's quite performant. + +## How does it work? + +By building a stack of functions. + +_Wait, what?_ + +Okay, so let's suppose we want to compile the selector `a b` again, for right-to-left execution. We start by _parsing_ the selector, which means we turn the selector into an array of the building-blocks of the selector, so we can distinguish them easily. That's what the [`css-what`](https://github.com/fb55/css-what) module is for, if you want to have a look. + +Anyway, after parsing, we end up with an array like this one: + +```js +[ + { type: 'tag', name: 'a' }, + { type: 'descendant' }, + { type: 'tag', name: 'b' } +] +``` + +Actually, this array is wrapped in another array, but that's another story (involving commas in selectors). + +Now that we know the meaning of every part of the selector, we can compile it. That's where it becomes interesting. + +The basic idea is to turn every part of the selector into a function, which takes an element as its only argument. The function checks whether a passed element matches its part of the selector: If it does, the element is passed to the next turned-into-a-function part of the selector, which does the same. If an element is accepted by all parts of the selector, it _matches_ the selector and double rainbow ALL THE WAY. + +As said before, we want to do right-to-left execution with all the big O improvements nonsense, so elements are passed from the rightmost part of the selector (`b` in our example) to the leftmost (~~which would be `c`~~ of course `a`). + +_//TODO: More in-depth description. Implementation details. Build a spaceship._ + +## API + +```js +var CSSselect = require("css-select"); +``` + +#### `CSSselect(query, elems, options)` + +Queries `elems`, returns an array containing all matches. + +- `query` can be either a CSS selector or a function. +- `elems` can be either an array of elements, or a single element. If it is an element, its children will be queried. +- `options` is described below. + +Aliases: `CSSselect.selectAll(query, elems)`, `CSSselect.iterate(query, elems)`. + +#### `CSSselect.compile(query)` + +Compiles the query, returns a function. + +#### `CSSselect.is(elem, query, options)` + +Tests whether or not an element is matched by `query`. `query` can be either a CSS selector or a function. + +#### `CSSselect.selectOne(query, elems, options)` + +Arguments are the same as for `CSSselect(query, elems)`. Only returns the first match, or `null` if there was no match. + +### Options + +- `xmlMode`: When enabled, tag names will be case-sensitive. Default: `false`. +- `strict`: Limits the module to only use CSS3 selectors. Default: `false`. +- `rootFunc`: The last function in the stack, will be called with the last element that's looked at. Should return `true`. + +## Supported selectors + +_As defined by CSS 4 and / or jQuery._ + +* Universal (`*`) +* Tag (`<tagname>`) +* Descendant (` `) +* Child (`>`) +* Parent (`<`) * +* Sibling (`+`) +* Adjacent (`~`) +* Attribute (`[attr=foo]`), with supported comparisons: + * `[attr]` (existential) + * `=` + * `~=` + * `|=` + * `*=` + * `^=` + * `$=` + * `!=` * + * Also, `i` can be added after the comparison to make the comparison case-insensitive (eg. `[attr=foo i]`) * +* Pseudos: + * `:not` + * `:contains` * + * `:icontains` * (case-insensitive version of `:contains`) + * `:has` * + * `:root` + * `:empty` + * `:parent` * + * `:[first|last]-child[-of-type]` + * `:only-of-type`, `:only-child` + * `:nth-[last-]child[-of-type]` + * `:link`, `:visited` (the latter doesn't match any elements) + * `:selected` *, `:checked` + * `:enabled`, `:disabled` + * `:required`, `:optional` + * `:header`, `:button`, `:input`, `:text`, `:checkbox`, `:file`, `:password`, `:reset`, `:radio` etc. * + * `:matches` * + +__*__: Not part of CSS3 + +--- + +License: BSD-like |