how to push an element at index 0 of an array

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How to insert an item into an array at a specific index? 10 answers

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使用Array#unshift方法。

var array1 = ["fruit", "vegetables"],
  array2 = [
    ["apple", "banana"],
    ["tomato"]
  ];

var array3 = array2.map(function(v, i) { // iterate over the array to generate the new array
  var arr = v.slice(); // copy the array
  arr.unshift(array1[i]) // insert element at beginning 
  return arr; /// return generated array
});

console.log(array3)

---

Try this Array.map() and Array.unshift() . unshift() push the data into array [0]index position.

array1 = ["fruit","vegetables"];
array2 = [["apple","banana"],["tomato"]]; 

array2.map((a,i) =>  a.unshift(array1[i]))
console.log(array2)

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