Javascript operations for duplicating and altering arrays

In my Angular application, I am working with an array called subAgencies that is connected to a datasource. I need to implement 2-way binding on this array. Currently, I have a method in place where I copy the contents of the original array to a new one, make modifications, and then re-assign it back to the original. While this approach works, I feel like it is quite verbose.

this.subAgenciesOriginal = Object.assign([], this.subAgencies);
this.subAgencies = []
this.subAgenciesOriginal.splice(this.subAgenciesOriginal.findIndex(item => item.subAgencyId === subAgencyToRemove.subAgencyId), 1)
this.subAgencies = Object.assign([], this.subAgenciesOriginal);
arraysangulartypescript

Answer №1

This code is a bit hard to follow, I suggest utilizing the .map method for better readability

this.subAgencies = this.subAgenciesOriginal
    .map((item) => item.id === subAgencyToRemove.id 
        ? newValue 
        : item
    )

By using the .map method, it creates a new array where if the id matches the subAgencyToRemove id, it replaces the value, otherwise it keeps the same value. This ensures that items are kept in their original index

If the goal is simply to remove an item at a specific index, then the .filter method might be more efficient

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