Category: TypeScript

Sometimes, we want to remove whitespace from a string in TypeScript.

In this article, we’ll look at how to remove whitespace from a string in TypeScript.

How to remove whitespace from a string in TypeScript?

To remove whitespace from a string in TypeScript, we can use the string replace method.

For instance, we write

const out = "hello world".replace(/\s/g, "");
console.log(out);

to call replace on 'hello world' with a regex to match all whitespaces and replace them all with empty strings.

Conclusion

To remove whitespace from a string in TypeScript, we can use the string replace method.

Sometimes, we want to use the fs module in TypeScript.

in this article, we’ll look at how to use the fs module in TypeScript.

How to use the fs module in TypeScript?

To use the fs module in TypeScript, we can import the module with import.

For instance, we write

import * as fs from "fs";
import * as path from "path";

fs.readFile(
  path.join(__dirname, "./client/index.html"),
  "utf8",
  (error, data) => {
    // ...
  }
);

to import the fs module with

import * as fs from "fs";

Then we call fs.readFile with the path of the file we want to read.

Then we get the file data from the data parameter in the callback.

Sometimes, we want to use @types with TypeScript.

In this article, we’ll look at how to use @types with TypeScript.

How to use @types with TypeScript?

To use @types with TypeScript, we can install the package in the @types namespace that has the type definitions for the modules we’re using.

For instance, we run

npm install --save @types/lodash

to install the @types/lodash package in our project to add the TypeScript type definitions for the lodash module into our project.

Then the TypeScript compiler will get the type info from the type definition files and provide type checking and autocomplete functionality.

Conclusion

To use @types with TypeScript, we can install the package in the @types namespace that has the type definitions for the modules we’re using.

Sometimes, we want to set the return type for the array map method callback in TypeScript.

In this article, we’ll look at how to set the return type for the array map method callback in TypeScript.

How to set the return type for the array map method callback in TypeScript?

To set the return type for the array map method callback in TypeScript, we can set the return type of the callback with type assertion.

For instance, we write

interface IKeys {
  key1: string;
  key2: string;
}
array.map(
  (val) =>
    <IKeys>{
      key1: val.key1,
      key2: val.key2,
    }
);

to create the IKeys interface.

Then we call array.map with a callback that returns an IKeys object.

We set the return type of the callback with <IKeys> in front of the callback.

Conclusion

To set the return type for the array map method callback in TypeScript, we can set the return type of the callback with type assertion.

Sometimes, we want to use styled-components with props and TypeScript.

In this article, we’ll look at how to use styled-components with props and TypeScript.

How to use styled-components with props and TypeScript?

To use styled-components with props and TypeScript, we can create our own interface and use that as the type argument for the styled element function.

For instance, we write

interface Props {
  onPress: any;
  src: any;
  width: string;
  height: string;
}

const Icon = styled.Image<Props>`
  width: ${(p) => p.width};
  height: ${(p) => p.height};
`;

to use the styled.Image tag with the Props interface as the type argument.

And then we can get the width and height properties from the p prop parameter without errors.

Conclusion

To use styled-components with props and TypeScript, we can create our own interface and use that as the type argument for the styled element function.