algorithm - Finding All Combinations of JavaScript array values -

how can produce of combinations of values in n number of javascript arrays of variable lengths?

let's have n number of javascript arrays, e.g.

var first = ['a', 'b', 'c', 'd']; var second = ['e']; var third =  ['f', 'g', 'h', 'i', 'j']; 

(three arrays in example, n number of arrays problem.)

and want output combinations of values, produce

aef aeg aeh aei aej bef beg .... dej 

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edit: here's version got working, using ffriend's accepted answer basis.

var allarrays = [['a', 'b'], ['c', 'z'], ['d', 'e', 'f']];   function allpossiblecases(arr) {   if (arr.length === 0) {     return [];   }  else if (arr.length ===1){ return arr[0]; } else {     var result = [];     var allcasesofrest = allpossiblecases(arr.slice(1));  // recur rest of array     (var c in allcasesofrest) {       (var = 0; < arr[0].length; i++) {         result.push(arr[0][i] + allcasesofrest[c]);       }     }     return result;   }  } var r=allpossiblecases(allarrays);  //outputs ["acd", "bcd", "azd", "bzd", "ace", "bce", "aze", "bze", "acf", "bcf", "azf", "bzf"] 

this not permutations, see permutations definitions wikipedia.

but can achieve recursion:

var allarrays = [['a', 'b'], ['c'], ['d', 'e', 'f']]  function allpossiblecases(arr) {   if (arr.length == 1) {     return arr[0];   } else {     var result = [];     var allcasesofrest = allpossiblecases(arr.slice(1));  // recur rest of array     (var = 0; < allcasesofrest.length; i++) {       (var j = 0; j < arr[0].length; j++) {         result.push(arr[0][j] + allcasesofrest[i]);       }     }     return result;   }  } 

you can make loops, bit tricky , require implementing own analogue of stack.