Javascript merge to array with some identical value at certain index -

i have 2 arrays want combine (merge), if value @ index 0 first array identical value @ index 0 on second array must in same array. more details: array 1:

var arr1 = [     ["sp.22110000295", 1,      162.9],     ["sp29372",        1,     1061.6],     ["sp3204200014",   5,     1147.5],     ["sp324035",       1, 94110.0231] ]; 

array 2:

 var arr2  [     ["999974",           1],     ["sp.sambacr803805", 1],     ["sp29193",          1],     ["sp29372",          4],     ["sp324035",         3] ] 

as can see (in example), first array have 4 array 3 items, , second 5 array 2 items. arr1[3][0] (["sp324035", 1, 94110.0231]) equal arr2[4][0] (["sp324035", 1])

so don't know hot achieve result this:

var arrfinal = [    ["sp.22110000295",     1,      162.9, null], // arr1 index 0 **is not** in arr2 index 0    ["sp29372",            1,     1061.6,    4], // arr1 index 0 **is** in arr2 index 0    ["sp3204200014",       5,     1147.5, null], // arr1 index 0 **is not** in arr2 index 0    ["sp324035",           1, 94110.0231,    3], // arr1 index 0 **is** in arr2 index 0    ["999974",          null,       null,    1], // arr2 index 0 **is not** in arr1 index 0    ["sp.sambacr803805",null,       null,    1], // arr2 index 0 **is not** in arr1 index 0    ["sp29193",         null,       null,    1]  // arr2 index 0 **is not** in arr1 index 0 ]; 

actualy it's not realy merge, because arrays values of index 0 equals merged others it's kind of splice.

i tried merge, expand splice... underscore, jquery...

any hints please?

thank you, much, geo

what understand question have 2 arrays, arr1 , arr2, , want generate new array, arrfinal, folowing conditions

1. items arr1 should copied arrfinal
2. if there exists arrfinal[i][0] === arr2[j][0] i, j, items of arr[2][j] index 1 should appened end of items arr1[i] in arrfinal
3. if not happen, push new array arrfinal index 0 of arr2[j][0] padded nulls before appending other items arr2[j]
4. all items in arrfinal should have same length

var arrfinal = [],     key_map = {},     max_len_1 = 0,     max_len_2 = 0,     i, j;  (i = 0; < arr1.length; ++i) {     max_len_1 = math.max(max_len_1, arr1[i].length); // find maximum length of arr1     arrfinal.push(arr1[i].slice()); // copy final     key_map[arr1[i][0]] = arrfinal.length - 1; // mapping later }  (i = 0; < arrfinal.length; ++i) { // fix lengths     while (arrfinal[i].length < max_len_1) {         arrfinal[i].push(null);     } }  (i = 0; < arr2.length; ++i) {     max_len_2 = math.max(max_len_2, arr2[i].length); // find maximum length of arr2     if (key_map.hasownproperty(arr2[i][0])) { // entry exists arr1         j = key_map[arr2[i][0]];     } else { // generate new entry         j = arrfinal.push([arr2[i][0]]) - 1;         while (arrfinal[j].length < max_len_1) { // fix length             arrfinal[j].push(null);         }     }     array.prototype.push.apply(         arrfinal[j],         arr2[i].slice(1)     ); }  (i = 0; < arrfinal.length; ++i) { // fix lengths 1 last time     while (arrfinal[i].length < max_len_1 + max_len_2 - 1) {         arrfinal[i].push(null);     } } 

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it should noted however, may give unexpected results if there exists multiple items have same value @ index 0 per arr1 or arr2, example

var arr1 = [     [ 'foo',      1],     ['fizz', 'buzz'] ]; var arr2 = [     ['foo', 'bar']     ['foo', 'baz'] ]; 

would result in

[     [ 'foo',      1, 'bar', 'baz'],     ['fizz', 'buzz',  null       ] ] 

further, if these guaranteed unique perhaps should consider using object instead of array