I am trying to create an array out of a modified object but the Array<any>.push() method always appends the object that gets modified at the end of the loop. Here is sample code that I am trying to work with:
let data: any = JSON.parse('{"messages":[{"id":"1234"},{"id":"2345"},{"id":"3456"}]}');
let myObject:any;
let idMapping: any[] = [];
for(let index = 0; index < 1; index++) {
myObject = {DocID: "", index: index};
for (let val of data.messages) {
myObject.DocID = val.id;
// console.log("After update: ", myObject); // this gives me the correct object
idMapping.push(myObject);
}
}
console.log(idMapping) // array with same identical values, infact the last modified value in for loop
This is giving me a list of same objects against what I expected it to be a list of objects having different DocID.
I am new to typescript and Nodejs, so any help would be appreciated.
You modify and add the same object to the array over and over again!
Instead you should create a new object every iteration:
let data: any = JSON.parse('{"messages":[{"id":"1234"},{"id":"2345"},{"id":"3456"}]}');
let idMapping: any[] = [];
for(let index = 0; index < 1; index++) {
for (let val of data.messages) {
let myObject = {DocID: "", index: index};
myObject.DocID = val.id;
// console.log("After update: ", myObject); // this gives me the correct object
idMapping.push(myObject);
}
}
console.log(idMapping)