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    snapdragon-util

    5.0.1 • Public • Published

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    Utilities for the snapdragon parser/compiler.

    Please consider following this project's author, Jon Schlinkert, and consider starring the project to show your ❤️ and support.

    Install

    Install with npm:

    $ npm install --save snapdragon-util

    Usage

    var util = require('snapdragon-util');

    API

    .isNode

    Returns true if the given value is a node.

    Params

    Example

    var Node = require('snapdragon-node');
    var node = new Node({type: 'foo'});
    console.log(utils.isNode(node)); //=> true
    console.log(utils.isNode({})); //=> false

    .noop

    Emit an empty string for the given node.

    Params

    Example

    // do nothing for beginning-of-string
    snapdragon.compiler.set('bos', utils.noop);

    .value

    Returns node.value or node.val.

    Params

    Example

    const star = new Node({type: 'star', value: '*'});
    const slash = new Node({type: 'slash', val: '/'});
    console.log(utils.value(star)) //=> '*'
    console.log(utils.value(slash)) //=> '/'

    .identity

    Append node.value to compiler.output.

    Params

    Example

    snapdragon.compiler.set('text', utils.identity);

    .append

    Previously named .emit, this method appends the given value to compiler.output for the given node. Useful when you know what value should be appended advance, regardless of the actual value of node.value.

    Params

    • node {Object}: Instance of snapdragon-node
    • returns {Function}: Returns a compiler middleware function.

    Example

    snapdragon.compiler
      .set('i', function(node) {
        this.mapVisit(node);
      })
      .set('i.open', utils.append('<i>'))
      .set('i.close', utils.append('</i>'))

    .toNoop

    Used in compiler middleware, this onverts an AST node into an empty text node and deletes node.nodes if it exists. The advantage of this method is that, as opposed to completely removing the node, indices will not need to be re-calculated in sibling nodes, and nothing is appended to the output.

    Params

    • node {Object}: Instance of snapdragon-node
    • nodes {Array}: Optionally pass a new nodes value, to replace the existing node.nodes array.

    Example

    utils.toNoop(node);
    // convert `node.nodes` to the given value instead of deleting it
    utils.toNoop(node, []);

    .visit

    Visit node with the given fn. The built-in .visit method in snapdragon automatically calls registered compilers, this allows you to pass a visitor function.

    Params

    • node {Object}: Instance of snapdragon-node
    • fn {Function}
    • returns {Object}: returns the node after recursively visiting all child nodes.

    Example

    snapdragon.compiler.set('i', function(node) {
      utils.visit(node, function(childNode) {
        // do stuff with "childNode"
        return childNode;
      });
    });

    .mapVisit

    Map visit the given fn over node.nodes. This is called by visit, use this method if you do not want fn to be called on the first node.

    Params

    • node {Object}: Instance of snapdragon-node
    • options {Object}
    • fn {Function}
    • returns {Object}: returns the node

    Example

    snapdragon.compiler.set('i', function(node) {
      utils.mapVisit(node, function(childNode) {
        // do stuff with "childNode"
        return childNode;
      });
    });

    .addOpen

    Unshift an *.open node onto node.nodes.

    Params

    • node {Object}: Instance of snapdragon-node
    • Node {Function}: (required) Node constructor function from snapdragon-node.
    • filter {Function}: Optionaly specify a filter function to exclude the node.
    • returns {Object}: Returns the created opening node.

    Example

    var Node = require('snapdragon-node');
    snapdragon.parser.set('brace', function(node) {
      var match = this.match(/^{/);
      if (match) {
        var parent = new Node({type: 'brace'});
        utils.addOpen(parent, Node);
        console.log(parent.nodes[0]):
        // { type: 'brace.open', value: '' };
     
        // push the parent "brace" node onto the stack
        this.push(parent);
     
        // return the parent node, so it's also added to the AST
        return brace;
      }
    });

    .addClose

    Push a *.close node onto node.nodes.

    Params

    • node {Object}: Instance of snapdragon-node
    • Node {Function}: (required) Node constructor function from snapdragon-node.
    • filter {Function}: Optionaly specify a filter function to exclude the node.
    • returns {Object}: Returns the created closing node.

    Example

    var Node = require('snapdragon-node');
    snapdragon.parser.set('brace', function(node) {
      var match = this.match(/^}/);
      if (match) {
        var parent = this.parent();
        if (parent.type !== 'brace') {
          throw new Error('missing opening: ' + '}');
        }
     
        utils.addClose(parent, Node);
        console.log(parent.nodes[parent.nodes.length - 1]):
        // { type: 'brace.close', value: '' };
     
        // no need to return a node, since the parent
        // was already added to the AST
        return;
      }
    });

    .wrapNodes

    Wraps the given node with *.open and *.close nodes.

    Params

    • node {Object}: Instance of snapdragon-node
    • Node {Function}: (required) Node constructor function from snapdragon-node.
    • filter {Function}: Optionaly specify a filter function to exclude the node.
    • returns {Object}: Returns the node

    .pushNode

    Push the given node onto parent.nodes, and set parent as `node.parent.

    Params

    • parent {Object}
    • node {Object}: Instance of snapdragon-node
    • returns {Object}: Returns the child node

    Example

    var parent = new Node({type: 'foo'});
    var node = new Node({type: 'bar'});
    utils.pushNode(parent, node);
    console.log(parent.nodes[0].type) // 'bar'
    console.log(node.parent.type) // 'foo'

    .unshiftNode

    Unshift node onto parent.nodes, and set parent as `node.parent.

    Params

    • parent {Object}
    • node {Object}: Instance of snapdragon-node
    • returns {undefined}

    Example

    var parent = new Node({type: 'foo'});
    var node = new Node({type: 'bar'});
    utils.unshiftNode(parent, node);
    console.log(parent.nodes[0].type) // 'bar'
    console.log(node.parent.type) // 'foo'

    .popNode

    Pop the last node off of parent.nodes. The advantage of using this method is that it checks for node.nodes and works with any version of snapdragon-node.

    Params

    • parent {Object}
    • node {Object}: Instance of snapdragon-node
    • returns {Number|Undefined}: Returns the length of node.nodes or undefined.

    Example

    var parent = new Node({type: 'foo'});
    utils.pushNode(parent, new Node({type: 'foo'}));
    utils.pushNode(parent, new Node({type: 'bar'}));
    utils.pushNode(parent, new Node({type: 'baz'}));
    console.log(parent.nodes.length); //=> 3
    utils.popNode(parent);
    console.log(parent.nodes.length); //=> 2

    .shiftNode

    Shift the first node off of parent.nodes. The advantage of using this method is that it checks for node.nodes and works with any version of snapdragon-node.

    Params

    • parent {Object}
    • node {Object}: Instance of snapdragon-node
    • returns {Number|Undefined}: Returns the length of node.nodes or undefined.

    Example

    var parent = new Node({type: 'foo'});
    utils.pushNode(parent, new Node({type: 'foo'}));
    utils.pushNode(parent, new Node({type: 'bar'}));
    utils.pushNode(parent, new Node({type: 'baz'}));
    console.log(parent.nodes.length); //=> 3
    utils.shiftNode(parent);
    console.log(parent.nodes.length); //=> 2

    .removeNode

    Remove the specified node from parent.nodes.

    Params

    • parent {Object}
    • node {Object}: Instance of snapdragon-node
    • returns {Object|undefined}: Returns the removed node, if successful, or undefined if it does not exist on parent.nodes.

    Example

    var parent = new Node({type: 'abc'});
    var foo = new Node({type: 'foo'});
    utils.pushNode(parent, foo);
    utils.pushNode(parent, new Node({type: 'bar'}));
    utils.pushNode(parent, new Node({type: 'baz'}));
    console.log(parent.nodes.length); //=> 3
    utils.removeNode(parent, foo);
    console.log(parent.nodes.length); //=> 2

    .isType

    Returns true if node.type matches the given type. Throws a TypeError if node is not an instance of Node.

    Params

    • node {Object}: Instance of snapdragon-node
    • type {String}
    • returns {Boolean}

    Example

    var Node = require('snapdragon-node');
    var node = new Node({type: 'foo'});
    console.log(utils.isType(node, 'foo')); // false
    console.log(utils.isType(node, 'bar')); // true

    .hasType

    Returns true if the given node has the given type in node.nodes. Throws a TypeError if node is not an instance of Node.

    Params

    • node {Object}: Instance of snapdragon-node
    • type {String}
    • returns {Boolean}

    Example

    var Node = require('snapdragon-node');
    var node = new Node({
      type: 'foo',
      nodes: [
        new Node({type: 'bar'}),
        new Node({type: 'baz'})
      ]
    });
    console.log(utils.hasType(node, 'xyz')); // false
    console.log(utils.hasType(node, 'baz')); // true

    .firstOfType

    Returns the first node from node.nodes of the given type

    Params

    • nodes {Array}
    • type {String}
    • returns {Object|undefined}: Returns the first matching node or undefined.

    Example

    var node = new Node({
      type: 'foo',
      nodes: [
        new Node({type: 'text', value: 'abc'}),
        new Node({type: 'text', value: 'xyz'})
      ]
    });
     
    var textNode = utils.firstOfType(node.nodes, 'text');
    console.log(textNode.value);
    //=> 'abc'

    .findNode

    Returns the node at the specified index, or the first node of the given type from node.nodes.

    Params

    • nodes {Array}
    • type {String|Number}: Node type or index.
    • returns {Object}: Returns a node or undefined.

    Example

    var node = new Node({
      type: 'foo',
      nodes: [
        new Node({type: 'text', value: 'abc'}),
        new Node({type: 'text', value: 'xyz'})
      ]
    });
     
    var nodeOne = utils.findNode(node.nodes, 'text');
    console.log(nodeOne.value);
    //=> 'abc'
     
    var nodeTwo = utils.findNode(node.nodes, 1);
    console.log(nodeTwo.value);
    //=> 'xyz'

    .isOpen

    Returns true if the given node is an "*.open" node.

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({type: 'brace'});
    var open = new Node({type: 'brace.open'});
    var close = new Node({type: 'brace.close'});
     
    console.log(utils.isOpen(brace)); // false
    console.log(utils.isOpen(open)); // true
    console.log(utils.isOpen(close)); // false

    .isClose

    Returns true if the given node is a "*.close" node.

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({type: 'brace'});
    var open = new Node({type: 'brace.open'});
    var close = new Node({type: 'brace.close'});
     
    console.log(utils.isClose(brace)); // false
    console.log(utils.isClose(open)); // false
    console.log(utils.isClose(close)); // true

    .isBlock

    Returns true if the given node is an "*.open" node.

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({type: 'brace'});
    var open = new Node({type: 'brace.open', value: '{'});
    var inner = new Node({type: 'text', value: 'a,b,c'});
    var close = new Node({type: 'brace.close', value: '}'});
    brace.push(open);
    brace.push(inner);
    brace.push(close);
     
    console.log(utils.isBlock(brace)); // true

    .hasNode

    Returns true if parent.nodes has the given node.

    Params

    • type {String}
    • returns {Boolean}

    Example

    const foo = new Node({type: 'foo'});
    const bar = new Node({type: 'bar'});
    cosole.log(util.hasNode(foo, bar)); // false
    foo.push(bar);
    cosole.log(util.hasNode(foo, bar)); // true

    .hasOpen

    Returns true if node.nodes has an .open node

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({
      type: 'brace',
      nodes: []
    });
     
    var open = new Node({type: 'brace.open'});
    console.log(utils.hasOpen(brace)); // false
     
    brace.pushNode(open);
    console.log(utils.hasOpen(brace)); // true

    .hasClose

    Returns true if node.nodes has a .close node

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({
      type: 'brace',
      nodes: []
    });
     
    var close = new Node({type: 'brace.close'});
    console.log(utils.hasClose(brace)); // false
     
    brace.pushNode(close);
    console.log(utils.hasClose(brace)); // true

    .hasOpenAndClose

    Returns true if node.nodes has both .open and .close nodes

    Params

    Example

    var Node = require('snapdragon-node');
    var brace = new Node({
      type: 'brace',
      nodes: []
    });
     
    var open = new Node({type: 'brace.open'});
    var close = new Node({type: 'brace.close'});
    console.log(utils.hasOpen(brace)); // false
    console.log(utils.hasClose(brace)); // false
     
    brace.pushNode(open);
    brace.pushNode(close);
    console.log(utils.hasOpen(brace)); // true
    console.log(utils.hasClose(brace)); // true

    .addType

    Push the given node onto the state.inside array for the given type. This array is used as a specialized "stack" for only the given node.type.

    Params

    • state {Object}: The compiler.state object or custom state object.
    • node {Object}: Instance of snapdragon-node
    • returns {Array}: Returns the state.inside stack for the given type.

    Example

    var state = { inside: {}};
    var node = new Node({type: 'brace'});
    utils.addType(state, node);
    console.log(state.inside);
    //=> { brace: [{type: 'brace'}] }

    .removeType

    Remove the given node from the state.inside array for the given type. This array is used as a specialized "stack" for only the given node.type.

    Params

    • state {Object}: The compiler.state object or custom state object.
    • node {Object}: Instance of snapdragon-node
    • returns {Array}: Returns the state.inside stack for the given type.

    Example

    var state = { inside: {}};
    var node = new Node({type: 'brace'});
    utils.addType(state, node);
    console.log(state.inside);
    //=> { brace: [{type: 'brace'}] }
    utils.removeType(state, node);
    //=> { brace: [] }

    .isEmpty

    Returns true if node.value is an empty string, or node.nodes does not contain any non-empty text nodes.

    Params

    • node {Object}: Instance of snapdragon-node
    • fn {Function}
    • returns {Boolean}

    Example

    var node = new Node({type: 'text'});
    utils.isEmpty(node); //=> true
    node.value = 'foo';
    utils.isEmpty(node); //=> false

    .isInsideType

    Returns true if the state.inside stack for the given type exists and has one or more nodes on it.

    Params

    • state {Object}
    • type {String}
    • returns {Boolean}

    Example

    var state = { inside: {}};
    var node = new Node({type: 'brace'});
    console.log(utils.isInsideType(state, 'brace')); //=> false
    utils.addType(state, node);
    console.log(utils.isInsideType(state, 'brace')); //=> true
    utils.removeType(state, node);
    console.log(utils.isInsideType(state, 'brace')); //=> false

    .isInside

    Returns true if node is either a child or grand-child of the given type, or state.inside[type] is a non-empty array.

    Params

    • state {Object}: Either the compiler.state object, if it exists, or a user-supplied state object.
    • node {Object}: Instance of snapdragon-node
    • type {String}: The node.type to check for.
    • returns {Boolean}

    Example

    var state = { inside: {}};
    var node = new Node({type: 'brace'});
    var open = new Node({type: 'brace.open'});
    console.log(utils.isInside(state, open, 'brace')); //=> false
    utils.pushNode(node, open);
    console.log(utils.isInside(state, open, 'brace')); //=> true

    .last

    Get the last n element from the given array. Used for getting a node from node.nodes.

    Params

    • array {Array}
    • n {Number}
    • returns {undefined}

    .arrayify

    Cast the given value to an array.

    Params

    • value {any}
    • returns {Array}

    Example

    console.log(utils.arrayify(''));
    //=> []
    console.log(utils.arrayify('foo'));
    //=> ['foo']
    console.log(utils.arrayify(['foo']));
    //=> ['foo']

    .stringify

    Convert the given value to a string by joining with ,. Useful for creating a cheerio/CSS/DOM-style selector from a list of strings.

    Params

    • value {any}
    • returns {Array}

    .trim

    Ensure that the given value is a string and call .trim() on it, or return an empty string.

    Params

    • str {String}
    • returns {String}

    About

    Contributing

    Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

    Please read the contributing guide for advice on opening issues, pull requests, and coding standards.

    Running Tests

    Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:

    $ npm install && npm test
    Building docs

    (This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)

    To generate the readme, run the following command:

    $ npm install -g verbose/verb#dev verb-generate-readme && verb

    Related projects

    You might also be interested in these projects:

    Contributors

    Commits Contributor
    43 jonschlinkert
    2 realityking

    Author

    Jon Schlinkert

    License

    Copyright © 2018, Jon Schlinkert. Released under the MIT License.


    This file was generated by verb-generate-readme, v0.6.0, on January 11, 2018.

    Install

    npm i snapdragon-util

    DownloadsWeekly Downloads

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    Version

    5.0.1

    License

    MIT

    Last publish

    Collaborators

    • danez
    • jonschlinkert