Merge two sorted arrays into a sorted array of unique values from both

.gitignore

/node_modules
*.log
.DS_Store

.nvmrc

v4.3.1

.travis.yml

language: node_js

README.md

#merge-arrays

Merge two sorted arrays into a sorted array of unique values from both.

$ nvm use
$ npm install
$ npm test

fixtures.json

{
  "concat": [
    [ 17 ],
    [ 2, 6, 8, 10 ],
    [ 2, 6, 8, 10, 17 ]
  ],
  "same": [
    [ 1, 2, 3 ],
    [ 1, 2, 3 ],
    [ 1, 2, 3 ]
  ],
  "empty": [
    [ ],
    [ 2, 6 ],
    [ 2, 6 ]
  ],
  "both-empty": [
    [ ],
    [ ],
    [ ]
  ],
  "t1": [
    [ 1, 2, 3 ],
    [ 4, 5, 6 ],
    [ 1, 2, 3, 4, 5, 6 ]
  ],
  "t2": [
    [ 1, 11 ],
    [ 2, 3, 10 ],
    [ 1, 2, 3, 10, 11 ]
  ],
  "t3": [
    [ 2, 5, 6, 9 ],
    [ 1, 2, 3, 29 ],
    [ 1, 2, 3, 5, 6, 9, 29 ]
  ]
}

index.js

"use strict";

module.exports = (a, b) => {
  let c = [],
      i = 0,
      j = 0,
      last = null;
  while (i < a.length && j < b.length) {
    if (a[i] < b[j]) {
      if (a[i] != last) c.push(last = a[i]);
      i++;
    } else {
      if (b[j] != last) c.push(last = b[j]);
      j++;
    }
  }

  return c.concat((i != a.length) ? (a[i] != last) ? a.slice(i) : [] : (b[j] != last) ? b.slice(j) : []);
};

package.json

{
  "name": "merge-arrays",
  "version": "1.0.0",
  "author": "Radek Stepan <[email protected]>",
  "main": "index.js",
  "devDependencies": {
    "chai": "^3.5.0",
    "mocha": "^2.4.5"
  },
  "scripts": {
    "test": "./node_modules/.bin/mocha test.js --ui exports --bail --reporter spec"
  }
}

test.js

"use strict";

let assert = require('chai').assert;

let lib = require('./index.js');
let fix = require('./fixtures.json');

for (let i in fix) {
  exports[`test ${i}`] = (done) => {
    assert.deepEqual(lib.apply(null, fix[i]), fix[i][2]);
    done();
  };
}