如何在TypeScript中为已有JSON数组内的对象添加键值对

Alright, I see where you're going wrong here—your current code uses push() twice, which adds two separate objects to the array instead of updating the first one. Let's fix this with a few straightforward approaches:

1. Directly Modify the Existing Object in the Array #

Once you've pushed the initial object into the array, you can access it via its index (since it's the first element, that's index 0) and add the new properties directly:

let someData : any [] = [];
// Push the initial object into the array
someData.push({ "a" : "a1", "b" : "b1" });
// Add new properties to the first (and only) object in the array
someData[0].c = "c1";
someData[0].d = "d1";

// Result: [{ "a": "a1", "b": "b1", "c": "c1", "d": "d1" }]

2. Create the Full Object Before Pushing #

If you know all the properties upfront, you can just build the complete object first and push it into the array—no need to modify it later:

let someData : any [] = [];
// Push the fully formed object right away
someData.push({ "a" : "a1", "b" : "b1", "c" : "c1", "d" : "d1" });

3. Use Object Spread for Immutable Updates (Optional) #

If you prefer not to mutate the original object (a common practice in state management), use the object spread operator to create a new merged object, then replace the array element:

let someData : any [] = [];
someData.push({ "a" : "a1", "b" : "b1" });

// Merge original properties with new ones into a new object
const updatedObject = { ...someData[0], c: "c1", d: "d1" };
// Replace the old object in the array with the updated version
someData[0] = updatedObject;

All these methods will give you the single updated object in the array you're aiming for, instead of adding a second separate object.

内容的提问来源于stack exchange，提问作者user2000189