In TypeScript, dictionaries are data structures that allow storing key-value pairs efficiently and accessibly. These structures are especially useful when you need to access values by unique keys. A dictionary in TypeScript can be represented using objects or the Record<T, U> interface, where T represents the type of keys and U the type of associated values.
For example, we can define a dictionary to store word definitions, as follows:
const Dictionary {
[key: string]: string;}
let dictionary: Dictionary = {
‘hello’: ‘Informal greeting’,
‘run’: ‘To move rapidly and with such force that, between one step and the next, the feet or legs are momentarily off the ground’,
};
console.log(dictionary[‘run’]);
In this example, Dictionary is an interface that defines an object type where each key is a string and each associated value is also a string. Then, we create an instance of this dictionary called dictionary, where we store the definitions of two words: “hello” and “run”.
How to use Dictionaries in Typescript?
To access the values of the dictionary, we simply use the corresponding key, either through dot syntax (e.g., dictionary.hello) or bracket syntax (e.g., dictionary[‘run’]), the latter being necessary when the key name is a variable or not a valid JavaScript identifier.
