Selector Tokenizer

Module for fast css selector tokenization from string

What does this repo about

The selector tokenizer allows to break a css selector string into set of tokens.

The tokenization method is based on a set of lexer grammars rules. The full list of available token types is next:

• <type-selector> - for basic type selectors eg. "article", "h1", "p" etc.
• <class-selector> - for basic class selectors eg. ".button", ".post", etc.
• <universal-selector> - for basic universal selector "*"
• <attribute-selector> - for basic attribute selectors eg. "[attr]", "[attr=val]", "[attr^=val]" etc.
• <pseudo-selector> - for pseudo-element and pseudo-class-selectors eg. ":first-child", "::first-letter"
• <descendant-selector> - for selector's descendant combinator " "
• <adjacent-sibling-selector> - for selector's adjacent sibling combinator "+"
• <general-sibling-selector> - for selector's general sibling combinator "~"
• <child-selector> - for selector's child combinator ">"
• <scope-start> - to match the start of tokenization scopes ()
• <scope-end> - to match the end of tokenization scopes ()

How to use

Basic Example

The following example illustrates the principle the SelectorTokenizer.tokenize method

tokenizer = new SelectorTokenizer();
tokens = tokenizer.tokenize(".page main");
tokens   //=> [{type: "class", value: ".page"}, {type: "descendant", value: " "}, {type: "type", value: "main"}]

Methods

SelectorTokenizer has a set of different methods you can find to be useful.

tokenize(selectorText);

Create a set of tokens from target selector string

tokenizer = new SelectorTokenizer();
tokens = tokenizer.tokenize(".page main");
tokens   //=> [{type: "class", value: ".page"}, {type: "descendant", value: " "}, {type: "type", value: "main"}]

tokenAt(selectorText, startIndex);

Read a grammar token from a string starting at target position.

tokenizer = new SelectorTokenizer();
token = tokenizer.tokenAt(".classname", 0);
token   //=> { type: "class", value: ".classname" }

Building

npm install

Development and Testing

• npm run gulp will launch dist building
• npm run watch will launch a watcher for dist building
• npm run test will launch unit-test building
• npm run test-watch will launch a watcher for unit-test building

License

It's all about MIT stuff. (C) 2017 Eugene Ford