feat(parse): add method to parse files

Fixes #33

lib/index.js

@@ -11,5 +11,6 @@ module.exports = {
     },
     merge: require('./merge'),
     subtract: require('./subtract'),
-    intersect: require('./intersect')
+    intersect: require('./intersect'),
+    parse: require('./parse')
 };

lib/parse.js

@@ -0,0 +1,39 @@
+'use strict';
+
+const normalize = require('./normalize');
+const normalize2 = require('./normalize-harmony');
+
+const normalizers = {
+    '1.0': normalize,
+    '2.0': normalize2,
+    next: normalize2
+};
+
+/**
+ * Parses BEMDECL file data
+ *
+ * @param {{version: string, decl: BEMEntityPart[]}|{blocks: BEMEntityPart[]}} bemdecl [description]
+ * @returns {[type]}        [description]
+ */
+module.exports = function parse(bemdecl) {
+    const hasOwn = Object.prototype.hasOwnProperty.bind(Object(bemdecl));
+
+    let version, decl;
+
+    // Legacy 1.0 format
+    if (hasOwn('blocks')) {
+        version = '1.0';
+        decl = bemdecl.blocks;
+    } else if (hasOwn('version') && hasOwn('decl')) {
+        version = bemdecl.version;
+        decl = bemdecl.decl;
+    }
+
+    const normalizer = normalizers[version];
+
+    if (!decl || !normalizer) {
+        throw new Error('Unknown BEMDECL format.');
+    }
+
+    return normalizer(decl);
+};

test/index.test.js

@@ -30,3 +30,7 @@ test('should have `merge` method', t => {
 test('should have `subtract` method', t => {
     t.truthy(typeof bemDecl.subtract === 'function');
 });
+
+test('should have `parse` method', t => {
+    t.truthy(typeof bemDecl.parse === 'function');
+});

test/parse/common.test.js

@@ -0,0 +1,12 @@
+'use strict';
+
+const test = require('ava');
+const parse = require('../..').parse;
+
+test('should throw if undefined', t => {
+    t.throws(() => parse(), /Unknown BEMDECL format/);
+});
+
+test('should throw if unsupported', t => {
+    t.throws(() => parse({ version: 'unknown', components: [] }), /Unknown BEMDECL format/);
+});

test/parse/legacy.test.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const test = require('ava');
+const parse = require('../..').parse;
+
+test('should parse empty legacy blocks property', t => {
+    t.deepEqual(parse({ blocks: [] }), []);
+});
+
+test('should parse blocks property with single entity', t => {
+    t.deepEqual(parse({ blocks: [{ name: 'doesnt-matter' }] }),
+        [{ block: 'doesnt-matter' }]);
+});

test/parse/v1.test.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const test = require('ava');
+const parse = require('../..').parse;
+
+test('should parse empty legacy blocks property', t => {
+    t.deepEqual(parse({ version: '1.0', decl: [] }), []);
+});
+
+test('should parse blocks property with single entity', t => {
+    t.deepEqual(parse({ version: '1.0', decl: [{ name: 'doesnt-matter' }] }),
+        [{ block: 'doesnt-matter' }]);
+});

test/parse/v2.test.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const test = require('ava');
+const parse = require('../..').parse;
+
+test('should parse empty legacy blocks property', t => {
+    t.deepEqual(parse({ version: '2.0', decl: [] }), []);
+});
+
+test('should parse blocks property with single entity', t => {
+    t.deepEqual(parse({ version: '2.0', decl: [{ block: 'doesnt-matter' }] }),
+        [{ block: 'doesnt-matter' }]);
+});