JavaScript: Create a function that invokes fn with partials prepended to the arguments it receives

JavaScript fundamental (ES6 Syntax): Exercise-170 with Solution

Function with Prepended Partials

Write a JavaScript program to create a function that invokes fn with partials prepended to the arguments it receives.

• Use the spread operator (...) to prepend partials to the list of arguments of fn.

Sample Solution:

JavaScript Code:

// Define a function 'partial' that partially applies arguments to the left side of a function 'fn'
const partial = (fn, ...partials) => (...args) => fn(...partials, ...args);
// Define a function 'greet' that concatenates a 'greeting' string and a 'name' string with an exclamation mark
const greet = (greeting, name) => greeting + ' ' + name + '!';
// Partially apply the 'greeting' argument as 'Hello' to the 'greet' function using 'partial'
const greetHello = partial(greet, 'Hello');
// Call the partially applied function 'greetHello' with the 'name' argument as 'John'
console.log(greetHello('John'));

Output:

Hello John!

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-170-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that creates a new function which prepends fixed arguments to the arguments supplied during invocation.
• Write a JavaScript function that implements partial application by binding the first few parameters and deferring the rest.
• Write a JavaScript program that wraps a function to automatically add preset arguments at the beginning of its parameter list.
• Write a JavaScript function that shows how to prepend arguments to a function call and then passes the remaining arguments normally.

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