Merge Lists

index.html

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/1.2.1/lodash.min.js" type="text/javascript" />

merge-lists.markdown

Merge Lists

A Pen by rjchicago on CodePen.

License.

script.js

const merge = (lists, key) => {
		const o = {};
    _.each(lists, (list) => {
    		_.each(list, (item) => {
            // order of the lists matters, preserve prior values and do not overwrite...
        		if (typeof item[key] !== 'undefined' && typeof o[item[key]] === 'undefined') {
        				o[item[key]] = item;
            }
        });
    });
    return _.map(o, (value, key) => { return value; });
};


const lists = [
	[{key:0, value:'list0 key0'},{key:1, value:'list0 key1'},{key:2, value:'list0 key2'}],
	[{key:0, value:'list1 key0'},{key:10, value:'list1 key10'},{key:20, value:'list1 key20'}],
	[{key:0, value:'list2 key0'},{key:10, value:'list2 key10'},{key:200, value:'list2 key200'}],
];

const list = merge(lists, 'key');

console.log(JSON.stringify(list));