在一个数组中所有元素组合可能性遍历

var a=[['a1','a2'],['b1','b2'],['c1']];
var r = [];
 
for(i=0; i<a.length; i++) {
    len = r.length;
    for(v in a[i]) r.push([a[i][v]]);
    for(j=0; j<len; j++) {
      for(v in a[i]) 
        r.push(r[j].concat(a[i][v]));
    }
}

[[“a1”],[“a2”],[“b1”],[“b2”],[“a1”,“b1”],[“a1”,“b2”],[“a2”,“b1”],[“a2”,“b2”],[“c1”],[“a1”,“c1”],[“a2”,“c1”],[“b1”,“c1”],[“b2”,“c1”],[“a1”,“b1”,“c1”],[“a1”,“b2”,“c1”],[“a2”,“b1”,“c1”],[“a2”,“b2”,“c1”]] 必要的话，你就再按子数组长度排个序

r.sort(function(a, b){ return a.length-b.length;});

[[“a1”],[“a2”],[“b1”],[“b2”],[“c1”],[“a1”,“b1”],[“a1”,“b2”],[“a2”,“b1”],[“a2”,“b2”],[“a1”,“c1”],[“a2”,“c1”],[“b1”,“c1”],[“b2”,“c1”],[“a1”,“b1”,“c1”],[“a1”,“b2”,“c1”],[“a2”,“b1”,“c1”],[“a2”,“b2”,“c1”]]