assign a random name to the "attribute" of any object

Question

assign a random name to the "attribute" of any object

I recently started using TypeScript and I have a question about the syntax. I came across some code that defines a parameter like this:

{ [property: string]: any}

I'm a bit confused because I understand that the parameter should be an object and its property should be a string. But can't I just change "property" to any random name, like:

{ [SomeNonSenseName: string]: any}

And it still functions the same way as before, so does the property name really matter if we don't need to reference it? Is this a design flaw in TypeScript?

javascript typescript

Answer 1

Answer №1

It's important to understand that the property name is not significant and will not be used in further references.

Yes, but it does ensure that indexed property keys are of type string. You can also define additional properties explicitly if needed.

Keep in mind that the property name can serve a purpose for documentation, such as creating a dictionary of arguments with values like this: { [argName: string]: string }

Answer 2

It's important to understand that the property name is not significant and will not be used in further references.

Yes, but it does ensure that indexed property keys are of type string. You can also define additional properties explicitly if needed.

Keep in mind that the property name can serve a purpose for documentation, such as creating a dictionary of arguments with values like this: { [argName: string]: string }

Answer 3

Answer №2

The phrase { [key: string]: any} is used to define what is known as an Indexable Type

This means we can specify types that we are able to access with an index like a[10], or ageMap["daniel"]. Indexable types come with an index signature that outlines the types available for indexing into the object, and their corresponding return types.

There are two kinds of supported index signatures: string and number.

In simpler terms, this declaration indicates that you have an Object which may contain multiple properties, where each property is assigned the type of any.

The use of the term property in this syntax refers to the indexer signature rather than the specific name of a property.

let user: { [key: string]: any}  = { name: 'John', age: 30};
console.log(user['name']) 
console.log(user['age']) 
user['city'] = 'NY'
console.log(user['city'])

Answer 4

The phrase { [key: string]: any} is used to define what is known as an Indexable Type

This means we can specify types that we are able to access with an index like a[10], or ageMap["daniel"]. Indexable types come with an index signature that outlines the types available for indexing into the object, and their corresponding return types.

There are two kinds of supported index signatures: string and number.

In simpler terms, this declaration indicates that you have an Object which may contain multiple properties, where each property is assigned the type of any.

The use of the term property in this syntax refers to the indexer signature rather than the specific name of a property.

let user: { [key: string]: any}  = { name: 'John', age: 30};
console.log(user['name']) 
console.log(user['age']) 
user['city'] = 'NY'
console.log(user['city'])

assign a random name to the "attribute" of any object

Answer №1

Answer №2

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