Function Expression

A function declaration is a standalone statement. But sometimes it is helpful to define a function as part of another expression, e.g., in an assignment, as a function parameter (callback) or as value in an Objects. This can be done with a function expression. It has the same syntax as a function declaration, only that the function name can be omitted to create an anonymous function.

const someFunction = function (param) {
  // ...
};

someOtherFunction(function (param) {
  // ...
});

const obj = {
  someFunction: function (param) {
    // ...
  },
};

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References:

• https://exercism.org/tracks/javascript/concepts/functions
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/function

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Backlinks

• Functions
• Arrow Functions