Author: John Au-Yeung

Sometimes, we want to cast a number to a string in TypeScript.

In this article, we’ll look at how to cast a number to a string in TypeScript.

How to cast a number to a string in TypeScript?

To cast a number to a string in TypeScript,. we can use the toString method.

For instance, we write

const pageNumber: number = 3;
const s: string = pageNumber.toString();

to call pageNumber.toString to return the number converted into a number string and then assign the string to s.

Conclusion

To cast a number to a string in TypeScript,. we can use the toString method.

Sometimes, we want to create an empty typed container array with TypeScript.

In this article, we’ll look at how to create an empty typed container array with TypeScript.

How to create an empty typed container array with TypeScript?

To create an empty typed container array with TypeScript, we can create the variable and set it to the array type or we can cast an existing to the array type.

For instance, we write

const arr: Fruit[] = [];

to create the arr array to a Fruit array type.

We can also cast an array to the type we want by writing

const arr = <Fruit[]>[];

Conclusion

To create an empty typed container array with TypeScript, we can create the variable and set it to the array type or we can cast an existing to the array type.

To fix the "Property ‘value’ does not exist on type ‘Readonly<{}>’ " error with React TypeScript, we should specify the prop and state types in our React class component.

For instance, we write

type MyProps = {
  //...
};
type MyState = { value: string };
class App extends React.Component<MyProps, MyState> {
  //...
}

to specify the MyProps and MyState types as the types for the props and state of our React class component with

React.Component<MyProps, MyState>

We should add value into the type specification since it’s specified in the error.

Sometimes, we want to add types for key-value pairs in TypeScript.

In this article, we’ll look at how to add types for key-value pairs in TypeScript.

How to add types for key-value pairs in TypeScript?

To add types for key-value pairs in TypeScript, we can use index signatures.

For instance, we write

interface Foo {
  [key: string]: number;
}

const foo: Foo = {};
foo["hello"] = 123;

to create the Foo interface that accepts any key-value pairs that have numbers as their values with

[key: string]: number;

Then we can create an object that implements the interface with

const foo: Foo = {};
foo["hello"] = 123;

Conclusion

To add types for key-value pairs in TypeScript, we can use index signatures.

Sometimes, we want to fix the "Build:No inputs were found in config file" with the TypeScript tsconfig.json file.

In this article, we’ll look at how to fix the "Build:No inputs were found in config file" with the TypeScript tsconfig.json file.

How to fix the "Build:No inputs were found in config file" with the TypeScript tsconfig.json file?

To fix the "Build:No inputs were found in config file" with the TypeScript tsconfig.json file, we should make sure the source code path is in the include array in tsconfig.json.

For instance, we write

{
  //...
  "include": ["./src/"]
}

in tsconfig.json to set the ./src/ path as one of the path that has TypeScript code files.

Then then TypeScript compiler will compile the code in the directories listed in include.

Conclusion

To fix the "Build:No inputs were found in config file" with the TypeScript tsconfig.json file, we should make sure the source code path is in the include array in tsconfig.json.