BemjsonNode

BEM tree node representation.

Contents

• Install

• Usage

• API

• Serialization

• Debuggability

Install

$ npm install --save @bem/sdk.bemjson-node

Usage

const BemjsonNode = require('@bem/sdk.bemjson-node');

const bemjsonNode = new BemjsonNode({ block: 'button', elem: 'text' });

bemjsonNode.block;     // button
bemjsonNode.elem;      // text
bemjsonNode.mods;      // {}
bemjsonNode.elemMods;  // {}

API

• constructor({ block, mods, elem, elemMods, mix })

• block

• elem

• mods

• elemMods

• mix

• valueOf()

• toJSON()

• toString()

• static isBemjsonNode(bemjsonNode)

constructor({ block, mods, elem, elemMods, mix })

const BemjsonNode = require('@bem/sdk.bemjson-node');

// The block with modifier
new BemjsonNode({
    block: 'button',
    mods: { view: 'action' }
});

// The element inside block with modifier
new BemjsonNode({
    block: 'button',
    mods: { view: 'action' },
    elem: 'inner'
});

// The element node with modifier
new BemjsonNode({
    block: 'button',
    elem: 'icon',
    elemMods: { type: 'load' }
});

// The block with a mixed element
new BemjsonNode({
    block: 'button',
    mix: { block: 'button', elem: 'text' }
});

// Invalid value in mods field
new BemjsonNode({
    block: 'button',
    mods: 'icon'
});
// ➜ AssertionError: @bem/sdk.bemjson-node: `mods` field should be a simple object or null.

block

The name of block to which entity in this node belongs.

const BemjsonNode = require('@bem/sdk.bemjson-node');
const name = new BemjsonNode({ block: 'button' });

name.block; // button

elem

The name of element to which entity in this node belongs.

Important: Contains null value if node is a block entity.

const BemjsonNode = require('@bem/sdk.bemjson-node');
const node1 = new BemjsonNode({ block: 'button' });
const node2 = new BemjsonNode({ block: 'button', elem: 'text' });

node1.elem; // null
node2.elem; // "text"

mods

The object with modifiers of this node.

Important: Contains modifiers of a scope (block) node if this node IS an element.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const blockNode = new BemjsonNode({ block: 'button' });
const modsNode = new BemjsonNode({ block: 'button', mods: { disabled: true } });
const elemNode = new BemjsonNode({ block: 'button', mods: { disabled: true }, elem: 'text' });

blockNode.mods; // { }
elemNode.mods;  // { disabled: true }
modsNode.mods;  // { disabled: true }

elemMods

The object with modifiers of this node.

Important: Contains null if node IS NOT an element.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const blockNode = new BemjsonNode({ block: 'button' });
const modsNode = new BemjsonNode({ block: 'button', mods: { disabled: true } });
const elemNode = new BemjsonNode({ block: 'button', elem: 'text' });
const emodsNode = new BemjsonNode({ block: 'button', elem: 'text', elemMods: { highlighted: true } });

blockNode.elemMods; // null
modsNode.elemMods;  // null
elemNode.elemMods;  // { }
emodsNode.elemMods; // { disabled: true }

valueOf()

Returns normalized object representing the bemjson node.

const BemjsonNode = require('@bem/sdk.bemjson-node');
const node = new BemjsonNode({ block: 'button', mods: { focused: true }, elem: 'text' });

node.valueOf();

// ➜ { block: 'button', mods: { focused: true }, elem: 'text', elemMods: { } }

toJSON()

Returns raw data for JSON.stringify() purposes.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const node = new BemjsonNode({ block: 'input', mods: { available: true } });

JSON.stringify(node); // {"block":"input","mods":{"available":true}}

toString()

Returns string representing the bemjson node.

const BemjsonNode = require('@bem/sdk.bemjson-node');
const node = new BemjsonNode({
    block: 'button', mods: { focused: true },
    mix: { block: 'mixed', mods: { bg: 'red' } }
});

node.toString(); // "button _focused  mixed _bg_red"

static isBemjsonNode(bemjsonNode)

Determines whether specified object is an instance of BemjsonNode.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const bemjsonNode = new BemjsonNode({ block: 'input' });

BemjsonNode.isBemjsonNode(bemjsonNode); // true
BemjsonNode.isBemjsonNode({ block: 'button' }); // false

Serialization

The BemjsonNode has toJSON method to support JSON.stringify() behaviour.

Use JSON.stringify to serialize an instance of BemjsonNode.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const node = new BemjsonNode({ block: 'input', mod: 'available' });

JSON.stringify(node); // {"block":"input","mods":{"available":true}}

Use JSON.parse to deserialize JSON string and create an instance of BemjsonNode.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const str = '{"block":"input","mods":{"available"::true}}';

new BemjsonNode(JSON.parse(str)); // BemjsonNode({ block: 'input', mods: { available: true } });

Debuggability

In Node.js, console.log() calls util.inspect() on each argument without a formatting placeholder.

BemjsonNode has inspect() method to get custom string representation of the object.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const node = new BemjsonNode({ block: 'input', mods: { available: true } });

console.log(node);

// ➜ BemjsonNode { block: 'input', mods: { available: true } }

You can also convert BemjsonNode object to string.

const BemjsonNode = require('@bem/sdk.bemjson-node');

const node = new BemjsonNode({ block: 'input', mods: { available: true } });

console.log(`node: ${node}`);

// ➜ node: input _available

License

Code and documentation © 2017 YANDEX LLC. Code released under the Mozilla Public License 2.0.