我如何忽略 javascript 将前导零转换为八进制？

Question

I want to convert number to string , buti have a problem about javascript convert number that have leading zero to octal.

I have a list of object like this

const ids = [
  { _id : 1236 },
  { _id : "abc123" },
  { _id : 012019 },
  { _id : 000010 },
  { _id : 001230 }
  { _id : 00000000000000 }
]

and i want to convert all of id in object to string like this

[
  { _id : "1236" },
  { _id : "abc123" },
  { _id : "012345" },
  { _id : "000010 },
  { _id : "001230" },
  { _id : "00000000000000" }
]

So, i write a function like this

updateIds = () => ids.map(i => {
  i._id = i._id.toString()
  return i
})

updateIds()

But the result of this function is..

[
  { _id: '1236' },
  { _id: 'abc123' },
  { _id: '012019' },
  { _id: '8' },
  { _id: '664' },
  { _id: '0' }
]

how can i ignore javascript convert 000010 and 001230 to octal?

Ps. I think i cant use pad function to write leading zero because value of _id is dynamic. i don't know that length.

Answer 1

You have to define the base you want to use in the toString call.

If you want the ids to be parsed as base 10, then called toString(10) . It's impossible to do the padding to preserve the length because numbers are numbers, so leading zeros are ignored. You can pad to a fixed length, for all the ids:

updateIds = () => ids.map(i => {
  i._id = i._id.toString(10).padStart(9, '0');
  return i
})

Answer 2

Use Constructor call Number("001230") . It will convert all numbers to base 10 only, so you won't have the octal conversion problem

const ids = [
  { _id : 1236 },
  { _id : "abc123" },
  { _id : 012019 },
  { _id : 000010 },
  { _id : 001230 },
  { _id : 00000000000000 }
];

let ans = [];

ids.forEach((val)=>{

    let obj = {};
    obj._id = Number(val["_id"]);
    ans.push(obj);

})

console.log(ans);