"如何使用来自平面JSON的第一个条目作为javascript中的父项创建嵌套JSON"

Question

I've tried various answers to this (same\/similar) question here, and none have given the desired result. I have a flat Json file that I need to convert to nested. The first item in each chunk is the item that the data needs grouping on when converted to nested data. The example data just shows two "types" but there are several more in the data, and a few more other elements along with colour and size as well - I kept it short for posting here.

[
  {
    "type": "Background",
    "colour": "Blue",
    "size": "5"
  },
  {
    "type": "Background",
    "colour": "Grey",
    "size": "3"
  },
  {
    "type": "Foreground",
    "colour": "Red",
    "size": "5"
  },
  {
    "type": "Foreground",
    "colour": "White",
    "size": "10"
  }
]

Answer 1

You can use the forEach()<\/code> method to loop over the array, in this case, result<\/em> . If the type wasn't set in the result<\/em> , then add the new type. But, if the item already has its type in the result<\/em> , then just push the item's elements.

Answer 2

It seems that there are two steps here. First group all entries with the same type (which would be easier under the type name as a property, then build the nesting.

Answer 3

try this

var output = [];

var newObj = { type: input[0].type, elements: [] };
var prevType = input[0].type;

input.forEach((element) => {
  if (element.type != prevType) {
    output.push(newObj);
    newObj = { type: element.type, elements: [] };
    prevType = element.type;
  }
  newObj.elements.push({ colour: element.colour, size: element.size });
});
output.push(newObj);