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Lodash _.unary


The lodash _.unary method is a powerful utility function that accepts a single function as its input and returns a new function that accepts only a single argument regardless of how many arguments the original function takes. This new function can be helpful in several use cases where you want to ensure that a function is called with one and only one argument.

The _.unary method is part of the popular Lodash utility library, which provides a wide range of helper functions for everyday programming tasks. With the _.unary function, you can easily convert a function with multiple arguments into a function that expects only one argument.

The syntax of the _.unary method is simple. You can use it like:


Here, func is the original function that takes multiple arguments, and _.unary() returns a new function that takes only a single argument. For example:

function add(x, y) {
  return x + y;

const addUnary = _.unary(add);

console.log(addUnary(1, 2)); // Output: 3

console.log(addUnary(1, 2, 3, 4)); // Output: 3

As you can see, the addUnary() function created using _.unary only takes a single argument even though the original add() function expects two. In cases where a developer provides multiple arguments to the addUnary() function, only the first argument is used.

Using the _.unary method can be helpful in cases where you want to ensure a function is called with one and only one argument. For example, if you are using a function as an event handler for an event that provides more than one argument, you can use the _.unary method to create a new function that only accepts the first argument.

In conclusion, the _.unary method is a convenient tool for developers to convert a function with multiple arguments into a function that only accepts one argument. It simplifies programming tasks and can be helpful in a wide range of use cases.