Simple utility to check if a key or a value exists in an object.
Sponsors
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cannot get property x of undefined. Just returnsvoid 0(undefined) if a value or a key does not exist. Highly inspired from Java's Optional Type.
Index
- Installation
- Usage
- Simple Example
- Real World React Example
- Demos
- License
Installation
yarn
yarn add mjn
npm
npm install --save mjn
cdn
<script src="https://cdn.jsdelivr.net/npm/mjn@latest/dist/dist.min.js">script>
Usage
Simple Example
"no value!"
console.log(e); // => "I can be a function!"">import maybe from "mjn"; // Or import the library as you wish using npm or CDN script tag!
const myObject = {
user: {
name: "John",
surname: "Doe",
birthday: "1995-01-29",
contacts: {
email: "foo@bar.com",
phone: "000 0000000"
},
languages: ["english", "italian"]
}
};
const a = maybe(myObject, "user.name");
const b = maybe(myObject, "user.languages[1]");
const c = maybe(myObject, "foo.bar.baz");
const d = maybe(myObject, "foo.bar.baz", "no value!");
const e = maybe(myObject, "foo.bar.baz", () => "I can be a function!");
console.log(a); // => John
console.log(b); // => italian
console.log(c); // => won't log anything!
console.log(d); // => "no value!"
console.log(e); // => "I can be a function!"
const myObject = {
user: {
name: "John",
surname: "Doe",
birthday: "1995-01-29",
contacts: {
email: "foo@bar.com",
phone: "000 0000000"
},
languages: ["english", "italian"]
}
};
const a = maybe(myObject, "user.name");
const b = maybe(myObject, "user.languages[1]");
const c = maybe(myObject, "foo.bar.baz");
const d = maybe(myObject, "foo.bar.baz", "no value!");
const e = maybe(myObject, "foo.bar.baz", () => "I can be a function!");
console.log(a); // => John
console.log(b); // => italian
console.log(c); // => won't log anything!
console.log(d); // => "no value!"
console.log(e); // => "I can be a function!"
Real World React Example
import ReactDOM from "react-dom";
import maybe from "mjn";
const user = {
name: {
first_name: "John",
last_name: "Doe"
},
contacts: {
phone: "+00 000 0000000",
email: "john@doe.do"
}
};
const App = () => (
<div className="App">
<h1>Hello {maybe(user, "name.first_name")}!h1>
<h2> {maybe(user, "contacts.email")} h2>
<p>
{maybe(user, "contacts.phone.office", "You don't have an office phone.")}
p>
div>
);
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);