Getting a multidimensional array from JSON in Typescript: A step-by-step guide

Question

Getting a multidimensional array from JSON in Typescript: A step-by-step guide

Below is a sample of a JSON array containing information about cars.

var cars = {
    "cars": {
        "john": [],
        "alex": [
            "ford"
        ],
        "hilton": [],
        "martin": [
            "ford",
            "ferrari"
        ],
        "david": [
            "Lamborghini"
        ],
        ...
    }

}

I am looking to extract arrays from this data structure using Typescript but have been unsuccessful. I also have another JSON array with just names which I'm unable to utilize.

var names = { 
    "names": [
        "john",
        "alex",
        "hilton",
        "martin",
        "david",
        ...
    ]
}

Here is the approach I've tried, but it's not working as expected.


let aryCars: string[][] = [];
names.map((name: string) => {
    cars[name].map((car: string) => {
        aryCars[name].push(car);
    });
});

When attempting this, I encounter the following error:

Element implicitly has an 'any' type because index expression is not of type 'number'.

If you have any insights on how to solve this issue, please share. Thank you.

arrays json typescript multidimensional-array

Answer 1

Answer №1

It seems like the issue lies within these lines:

let carList: string[][] = [];

carList[name].push(car);

The problem here is that you've defined carList as an array with implicit numerical indexes, but you're trying to access it using a string variable name.

If your intention is to have carList structured differently, you might consider defining it like this:

const carList: { [key:string]: string[] } = {};

This way, carList will be an object with string keys and arrays of strings as values.

You can then modify your code to look something like this:

const carList: { [key:string]: string[] } = {};
names.forEach((make: string) => {
    carList[make] = cars[make]
});

Also note that if your 'names' variable is actually an object with a property named 'names', you would need to reference it as shown below:

names.names.forEach(...)

If this solution does not align with your desired outcome, please provide more information on what you expect the result to be.

Answer 2

It seems like the issue lies within these lines:

let carList: string[][] = [];

carList[name].push(car);

The problem here is that you've defined carList as an array with implicit numerical indexes, but you're trying to access it using a string variable name.

If your intention is to have carList structured differently, you might consider defining it like this:

const carList: { [key:string]: string[] } = {};

This way, carList will be an object with string keys and arrays of strings as values.

You can then modify your code to look something like this:

const carList: { [key:string]: string[] } = {};
names.forEach((make: string) => {
    carList[make] = cars[make]
});

Also note that if your 'names' variable is actually an object with a property named 'names', you would need to reference it as shown below:

names.names.forEach(...)

If this solution does not align with your desired outcome, please provide more information on what you expect the result to be.

Answer 3

Answer №2

String indexes are not supported in arrays. It is recommended to use an object type instead, like this:

let carObject: {
    [key: string]: string
} = {};

By using this approach, you can access the object using array notation.

Answer 4

String indexes are not supported in arrays. It is recommended to use an object type instead, like this:

let carObject: {
    [key: string]: string
} = {};

By using this approach, you can access the object using array notation.

Getting a multidimensional array from JSON in Typescript: A step-by-step guide

Answer №1

Answer №2

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