Combining arrays for use cases

Question

Node.js app, writing validation tests. Given the following:

var obj = { foo: null, bar: null, baz: null},
    values = [ 0, 1];

I need to

Answer 1

One way is to count from "000" to "999" in a values.length-based system:

keys = ['foo','bar','baz']
values = ['A', 'B']


width = keys.length
base = values.length
out = []

for(var i = 0; i < Math.pow(base, width); i++) {
  
  var d = [], j = i;
  
  while(d.length < width) {
    d.unshift(j % base)
    j = Math.floor(j / base)
  }
  
  var p = {};
  
  for(var k = 0; k < width; k++)
    p[keys[k]] = values[d[k]]

  out.push(p)
}  


document.write('
'+JSON.stringify(out,0,3))

Update for products:

'use strict';

let
    keys = ['foo', 'bar', 'baz'],
    values = [
        ['A', 'B'],
        ['a', 'b', 'c'],
        [0, 1]
    ];


let zip = (h, t) =>
    h.reduce((res, x) =>
        res.concat(t.map(y => [x].concat(y)))
    , []);

let product = arrays => arrays.length
    ? zip(arrays[0], product(arrays.slice(1)))
    : [[]];

let combine = (keys, values) =>
    keys.reduce((res, k, i) =>
        (res[k] = values[i], res)
        , {});

let z = product(values).map(v => combine(keys, v));

z.map(x => document.write('
'+JSON.stringify(x)+'
'))