how to use the partial function from lodash in javascript

The partial function from Lodash allows you to create a new function with some of the arguments of an existing function already set. This is useful when you want to reuse a function with some specific arguments, without having to send them every time the function is called.

Here's how you can use _.partial in JavaScript:

index.tsx
const func = (a, b, c) => {
  console.log(a, b, c);
};
// create a new function with `a` already set to `1`
const newFunc = _.partial(func, 1);
// call the new function with the remaining arguments
newFunc(2, 3); // logs: 1 2 3
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In the example above, we have an existing function called func that takes three arguments a, b, and c. We use _.partial to create a new function called newFunc with the first argument a already set to 1. When newFunc is called with the remaining arguments 2 and 3, it logs 1 2 3 to the console.

_.partial can also be used for currying, which is a technique in functional programming where a function that takes multiple arguments is transformed into a function that takes a single argument and returns another function that takes the next argument, and so on. Here's an example:

index.tsx
const sum = (a, b, c) => a + b + c;
// curry `sum` into a function that takes two arguments
const curriedSum = _.partial(sum, _, _, 10);
console.log(curriedSum(1, 2)); // logs: 13 (1 + 2 + 10)
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In this example, we use _.partial to create a new function called curriedSum that takes two arguments and returns the sum of those two arguments and 10. The _ symbol is used as a placeholder for the arguments that will be passed to the function later. When we call curriedSum with the arguments 1 and 2, it returns 13 since 1 + 2 + 10 = 13.

By using _.partial and currying, you can create reusable functions with fewer arguments that are easy to compose and work with in a functional programming style.