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snapdragon-util

Utilities for the snapdragon parser/compiler.

Table of Contents

Install
Usage
API
Release history
[3.0.0] - 2017-05-01
[0.1.0]
About

Install with npm:

$ npm install --save snapdragon-util

Install with yarn:

$ yarn add snapdragon-util

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

Returns true if the given value is a node.

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

Example

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

Emit an empty string for the given node.

Params

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

Example

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

Appdend node.val to compiler.output, exactly as it was created by the parser.

Params

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

Example

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

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

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>'))

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 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;
  });
});

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;
  });
});

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', val: '' };

    // 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;
  }
});

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', val: '' };

    // no need to return a node, since the parent
    // was already added to the AST
    return;
  }
});

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

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'

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'

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

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

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

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

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

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', val: 'abc'}),
    new Node({type: 'text', val: 'xyz'})
  ]
});

var textNode = utils.firstOfType(node.nodes, 'text');
console.log(textNode.val);
//=> 'abc'

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', val: 'abc'}),
    new Node({type: 'text', val: 'xyz'})
  ]
});

var nodeOne = utils.findNode(node.nodes, 'text');
console.log(nodeOne.val);
//=> 'abc'

var nodeTwo = utils.findNode(node.nodes, 1);
console.log(nodeTwo.val);
//=> 'xyz'

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

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

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

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

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

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

Returns true if node.nodes has an .open node

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

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

Returns true if node.nodes has a .close node

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

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

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

Params

node {Object}: Instance of snapdragon-node
returns {Boolean}

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

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'}] }

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: [] }

Returns true if node.val 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.val = 'foo';
utils.isEmpty(node); //=> false

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

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

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

Params

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

Cast the given val to an array.

Params

val {any}
returns {Array}

Example

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

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

Params

val {any}
returns {Array}

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

Params

str {String}
returns {String}

Changelog entries are classified using the following labels from keep-a-changelog:

added: for new features
changed: for changes in existing functionality
deprecated: for once-stable features removed in upcoming releases
removed: for deprecated features removed in this release
fixed: for any bug fixes

Custom labels used in this changelog:

dependencies: bumps dependencies
housekeeping: code re-organization, minor edits, or other changes that don't fit in one of the other categories.

Changed

.emit was renamed to .append
.addNode was renamed to .pushNode
.getNode was renamed to .findNode
.isEmptyNodes was renamed to .isEmpty: also now works with node.nodes and/or node.val

Added

.identity
.removeNode
.shiftNode
.popNode

First release.

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.

(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

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: