在 node.js 中读取文件是否保证项目的顺序

Question

In my node.js application I have test data file that I read to populate some inputs. The test file contains an array of objects.

I use for reading:

data = fs.readFileSync(fileName, "utf8");

My test file:

[
 {
  "firstname": "John",
  "lastname": "Doe",
  "birthdate": "01/01/1970"
 },
 {
  "firstname": "El",
  "lastname": "Maestro",
  "birthdate": "01/01/1989",
  "isDeleted": true
 }
]

So the question is - when I read this file is it guaranteed that I will always get object with name "John" at index 0, and "El" at index 1?

Answer 1

Arrays always ensures order in JS

BUT

Keys inside objects doesnot ensure order in JS, they are 'unordered key value pair'

To answer your question:

when I read this file is it guaranteed that I will always get object with name "John" at index 0, and "El" at index 1

yes

BUT

The keys in the resulting object can be unordered, eg: it can be

{
  "firstname": "John",
  "lastname": "Doe",
  "birthdate": "01/01/1970"
 }

or

{
  "lastname": "Doe",
  "birthdate": "01/01/1970",
  "firstname": "John"
 }

etc...