Navigating through arrays in typescript

I am interested in iterating through an array of objects and accessing the property values of each object in TypeScript.

In C#, this can be easily done using a foreach loop on the array.

However, it seems a bit different in TypeScript. While we can use a foreach loop, we don't have direct access to the complete object. How can we achieve this?

@Input() gridDefinitions: GridColumnDefinition[]   
 public test() {
     for (var def **in** this.gridDefinitions){
       var test = <GridColumnDefinition>this.selectedObject;
       let castedtype = <GridColumnDefinition>def; // this gives an error
    }  
 }

UPDATE: I have just discovered the solution. The issue lies in how the collection is being iterated. By using of instead of in, we can access the iterated object directly. Refer to TypeScript for-in statement for more information.

Answer №1

When using the for...in construct, you are able to iterate over the keys of an object. However, if you want to iterate over the items in an array, you will need to utilize the for..of loop.

for (var def of this.gridDefinitions){ // def is of the array item type no casting necessary 
    var test = <GridColumnDefinition>this.selectedObject;
} 

If you prefer, you can also leverage array methods like forEach, map, and reduce to manipulate arrays in a way that resembles the functionality of LINQ.

Answer №2

Make sure to iterate through the gridDefinitions using a foreach loop and specify the type for the variable def.

gridDefinitions.forEach((def: GridColumnDefinition) => {
       var test = <GridColumnDefinition>this.selectedObject;
       let castedtype = <GridColumnDefinition>def;
 })

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