Is there a simple way to convert an Index Signature (dictionary) to a Map efficiently?

Question

Is there a simple way to convert an Index Signature (dictionary) to a Map efficiently?

Currently, the only method I am aware of to convert Dictionary<K,V> (such as from Json.NET) to Map<K,V> in TypeScript involves the following steps:

const json = '{ "1": "one", "2": "two", "3": "three", "4": "four" }';
const dictionary = JSON.parse(json) as { [index: number]: string; };
const parsedMap = new Map<number, string>();
for (const i in dictionary) {
    if (!dictionary.hasOwnProperty(i)) { continue; }
    console.log(`dictionary[${i}]: ${dictionary[i]}`);
    parsedMap.set(parseInt(i, 10), dictionary[i]);
}
console.log(`parsedMap.size: ${parsedMap.size}`);
console.log(`parsedMap.get(4): ${parsedMap.get(4)}`);

Are there any built-in methods or libraries that simplify this conversion process? Is the current approach too verbose?

typescript json.net

Answer 1

Answer №1

In the event that your coding environment supports Object.entries():

const parsedMap = new Map(Object.entries(JSON.parse(json)))

Please be aware that this method will result in keys being treated as strings rather than numbers.

If you find yourself needing numeric keys, (or if you do not have access to Object.entries()), a slightly longer alternative is available:

const dictionary = JSON.parse(json);
const parsedMap = new Map(Object.keys(dictionary).map(
     k => [parseInt(k, 10), dictionary[k]] as [number, string]
));

Answer 2

In the event that your coding environment supports Object.entries():

const parsedMap = new Map(Object.entries(JSON.parse(json)))

Please be aware that this method will result in keys being treated as strings rather than numbers.

If you find yourself needing numeric keys, (or if you do not have access to Object.entries()), a slightly longer alternative is available:

const dictionary = JSON.parse(json);
const parsedMap = new Map(Object.keys(dictionary).map(
     k => [parseInt(k, 10), dictionary[k]] as [number, string]
));

Is there a simple way to convert an Index Signature (dictionary) to a Map efficiently?

Answer №1

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