snapdragon-util

Utilities for the snapdragon parser/compiler.

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Install

Install with npm:

1$ npm install --save snapdragon-util

Usage

1var util = require('snapdragon-util');

API

.isNode

Returns true if the given value is a node.

Params

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

Example

1var Node = require('snapdragon-node');
2var node = new Node({type: 'foo'});
3console.log(utils.isNode(node)); //=> true
4console.log(utils.isNode({})); //=> false

.noop

Emit an empty string for the given node.

Params

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

Example

1// do nothing for beginning-of-string
2snapdragon.compiler.set('bos', utils.noop);

.value

Returns node.value or node.val.

Params

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

Example

1const star = new Node({type: 'star', value: '*'});
2const slash = new Node({type: 'slash', val: '/'});
3console.log(utils.value(star)) //=> '*'
4console.log(utils.value(slash)) //=> '/'

.identity

Append node.value to compiler.output.

Params

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

Example

1snapdragon.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

1snapdragon.compiler
2  .set('i', function(node) {
3    this.mapVisit(node);
4  })
5  .set('i.open', utils.append('<i>'))
6  .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

1utils.toNoop(node);
2// convert `node.nodes` to the given value instead of deleting it
3utils.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

1snapdragon.compiler.set('i', function(node) {
2  utils.visit(node, function(childNode) {
3    // do stuff with "childNode"
4    return childNode;
5  });
6});

.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

1snapdragon.compiler.set('i', function(node) {
2  utils.mapVisit(node, function(childNode) {
3    // do stuff with "childNode"
4    return childNode;
5  });
6});

.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

1var Node = require('snapdragon-node');
2snapdragon.parser.set('brace', function(node) {
3  var match = this.match(/^{/);
4  if (match) {
5    var parent = new Node({type: 'brace'});
6    utils.addOpen(parent, Node);
7    console.log(parent.nodes[0]):
8    // { type: 'brace.open', value: '' };
9
10    // push the parent "brace" node onto the stack
11    this.push(parent);
12
13    // return the parent node, so it's also added to the AST
14    return brace;
15  }
16});

.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

1var Node = require('snapdragon-node');
2snapdragon.parser.set('brace', function(node) {
3  var match = this.match(/^}/);
4  if (match) {
5    var parent = this.parent();
6    if (parent.type !== 'brace') {
7      throw new Error('missing opening: ' + '}');
8    }
9
10    utils.addClose(parent, Node);
11    console.log(parent.nodes[parent.nodes.length - 1]):
12    // { type: 'brace.close', value: '' };
13
14    // no need to return a node, since the parent
15    // was already added to the AST
16    return;
17  }
18});

.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

1var parent = new Node({type: 'foo'});
2var node = new Node({type: 'bar'});
3utils.pushNode(parent, node);
4console.log(parent.nodes[0].type) // 'bar'
5console.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

1var parent = new Node({type: 'foo'});
2var node = new Node({type: 'bar'});
3utils.unshiftNode(parent, node);
4console.log(parent.nodes[0].type) // 'bar'
5console.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

1var parent = new Node({type: 'foo'});
2utils.pushNode(parent, new Node({type: 'foo'}));
3utils.pushNode(parent, new Node({type: 'bar'}));
4utils.pushNode(parent, new Node({type: 'baz'}));
5console.log(parent.nodes.length); //=> 3
6utils.popNode(parent);
7console.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

1var parent = new Node({type: 'foo'});
2utils.pushNode(parent, new Node({type: 'foo'}));
3utils.pushNode(parent, new Node({type: 'bar'}));
4utils.pushNode(parent, new Node({type: 'baz'}));
5console.log(parent.nodes.length); //=> 3
6utils.shiftNode(parent);
7console.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

1var parent = new Node({type: 'abc'});
2var foo = new Node({type: 'foo'});
3utils.pushNode(parent, foo);
4utils.pushNode(parent, new Node({type: 'bar'}));
5utils.pushNode(parent, new Node({type: 'baz'}));
6console.log(parent.nodes.length); //=> 3
7utils.removeNode(parent, foo);
8console.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

1var Node = require('snapdragon-node');
2var node = new Node({type: 'foo'});
3console.log(utils.isType(node, 'foo')); // false
4console.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

1var Node = require('snapdragon-node');
2var node = new Node({
3  type: 'foo',
4  nodes: [
5    new Node({type: 'bar'}),
6    new Node({type: 'baz'})
7  ]
8});
9console.log(utils.hasType(node, 'xyz')); // false
10console.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

1var node = new Node({
2  type: 'foo',
3  nodes: [
4    new Node({type: 'text', value: 'abc'}),
5    new Node({type: 'text', value: 'xyz'})
6  ]
7});
8
9var textNode = utils.firstOfType(node.nodes, 'text');
10console.log(textNode.value);
11//=> '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

1var node = new Node({
2  type: 'foo',
3  nodes: [
4    new Node({type: 'text', value: 'abc'}),
5    new Node({type: 'text', value: 'xyz'})
6  ]
7});
8
9var nodeOne = utils.findNode(node.nodes, 'text');
10console.log(nodeOne.value);
11//=> 'abc'
12
13var nodeTwo = utils.findNode(node.nodes, 1);
14console.log(nodeTwo.value);
15//=> 'xyz'

.isOpen

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

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({type: 'brace'});
3var open = new Node({type: 'brace.open'});
4var close = new Node({type: 'brace.close'});
5
6console.log(utils.isOpen(brace)); // false
7console.log(utils.isOpen(open)); // true
8console.log(utils.isOpen(close)); // false

.isClose

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

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({type: 'brace'});
3var open = new Node({type: 'brace.open'});
4var close = new Node({type: 'brace.close'});
5
6console.log(utils.isClose(brace)); // false
7console.log(utils.isClose(open)); // false
8console.log(utils.isClose(close)); // true

.isBlock

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

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({type: 'brace'});
3var open = new Node({type: 'brace.open', value: '{'});
4var inner = new Node({type: 'text', value: 'a,b,c'});
5var close = new Node({type: 'brace.close', value: '}'});
6brace.push(open);
7brace.push(inner);
8brace.push(close);
9
10console.log(utils.isBlock(brace)); // true

.hasNode

Returns true if parent.nodes has the given node.

Params

• type {String}
• returns {Boolean}

Example

1const foo = new Node({type: 'foo'});
2const bar = new Node({type: 'bar'});
3cosole.log(util.hasNode(foo, bar)); // false
4foo.push(bar);
5cosole.log(util.hasNode(foo, bar)); // true

.hasOpen

Returns true if node.nodes has an .open node

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({
3  type: 'brace',
4  nodes: []
5});
6
7var open = new Node({type: 'brace.open'});
8console.log(utils.hasOpen(brace)); // false
9
10brace.pushNode(open);
11console.log(utils.hasOpen(brace)); // true

.hasClose

Returns true if node.nodes has a .close node

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({
3  type: 'brace',
4  nodes: []
5});
6
7var close = new Node({type: 'brace.close'});
8console.log(utils.hasClose(brace)); // false
9
10brace.pushNode(close);
11console.log(utils.hasClose(brace)); // true

.hasOpenAndClose

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

Params

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

Example

1var Node = require('snapdragon-node');
2var brace = new Node({
3  type: 'brace',
4  nodes: []
5});
6
7var open = new Node({type: 'brace.open'});
8var close = new Node({type: 'brace.close'});
9console.log(utils.hasOpen(brace)); // false
10console.log(utils.hasClose(brace)); // false
11
12brace.pushNode(open);
13brace.pushNode(close);
14console.log(utils.hasOpen(brace)); // true
15console.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

1var state = { inside: {}};
2var node = new Node({type: 'brace'});
3utils.addType(state, node);
4console.log(state.inside);
5//=> { 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

1var state = { inside: {}};
2var node = new Node({type: 'brace'});
3utils.addType(state, node);
4console.log(state.inside);
5//=> { brace: [{type: 'brace'}] }
6utils.removeType(state, node);
7//=> { 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

1var node = new Node({type: 'text'});
2utils.isEmpty(node); //=> true
3node.value = 'foo';
4utils.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

1var state = { inside: {}};
2var node = new Node({type: 'brace'});
3console.log(utils.isInsideType(state, 'brace')); //=> false
4utils.addType(state, node);
5console.log(utils.isInsideType(state, 'brace')); //=> true
6utils.removeType(state, node);
7console.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

1var state = { inside: {}};
2var node = new Node({type: 'brace'});
3var open = new Node({type: 'brace.open'});
4console.log(utils.isInside(state, open, 'brace')); //=> false
5utils.pushNode(node, open);
6console.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

1console.log(utils.arrayify(''));
2//=> []
3console.log(utils.arrayify('foo'));
4//=> ['foo']
5console.log(utils.arrayify(['foo']));
6//=> ['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

1$ npm install && npm test

1$ npm install -g verbose/verb#dev verb-generate-readme && verb

Related projects

You might also be interested in these projects:

• snapdragon-node: Snapdragon utility for creating a new AST node in custom code, such as plugins. | homepage
• snapdragon-position: Snapdragon util and plugin for patching the position on an AST node. | homepage
• snapdragon-token: Create a snapdragon token. Used by the snapdragon lexer, but can also be used by… more | homepage

Contributors

Author

Jon Schlinkert

• linkedin/in/jonschlinkert
• github/jonschlinkert
• twitter/jonschlinkert

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.