Lodash _.functions() Method

Syntax, Parameter and Return Value

Syntax: 

_.functions(object)

Parameters:

object (Object): The object to inspect.

Return Value:

(Array) - Returns the array of function names.

Examples 

Listing Function Properties of an Object:

• JavaScript

JavaScript

var _ = require('lodash');

var myObject = {

  a: 1,

  b: 'string',

  c: function() { console.log('c'); },

  d: function() { console.log('d'); }

};

console.log(_.functions(myObject)); 

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Output: 

['c', 'd']

Demonstrates retrieving the names of function properties in an object.

Dynamic Method Invocation:

• JavaScript

JavaScript

var operations = {

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

  subtract: function(x, y) { return x - y; }

};

_.functions(operations).forEach(function(methodName) {

  console.log(methodName, operations[methodName](5, 3));

});

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Output:

 'add' 8, 'subtract' 2

Shows how to dynamically invoke methods listed by _.functions().

Filtering Methods for Documentation:

• JavaScript

JavaScript

var api = {

  getVersion: function() {},

  loadData: function() {},

  _privateMethod: function() {}

};

var publicMethods = _.functions(api).filter(name => !name.startsWith('_'));

console.log(publicMethods); var api = {

  getVersion: function() {},

  loadData: function() {},

  _privateMethod: function() {}

};

var publicMethods = _.functions(api).filter(name => !name.startsWith('_'));

console.log(publicMethods); 

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Output:

 ['getVersion', 'loadData']

An example of filtering out private methods (conventionally prefixed with '_') for documentation purposes.

Integrating with Other Lodash Methods:

• JavaScript

JavaScript

var complexObject = {

  prop: 'value',

  action: function() {},

  anotherAction: function() {}

};

var methodNames = _.chain(complexObject)

  .functions()

  .sort()

  .value();

console.log(methodNames); 

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Output:

 ['action', 'anotherAction']

Demonstrates combining _.functions() with other Lodash methods for custom processing.

Frequently Asked Questions

How does _.functions() differ from Object.keys()?

Object.keys() returns all own enumerable property names of an object, regardless of whether they are functions or not, while _.functions() specifically returns names of function properties.

Does _.functions() include inherited methods?

No, _.functions() only includes the function properties that are own properties of the object. It does not include inherited methods.

Can _.functions() be used with arrays?

While it can technically be used with arrays, _.functions() is most useful with objects, as arrays are typically used for storing data rather than methods.

Conclusion

Lodash's _.functions() method is a valuable tool for identifying the callable methods of an object. It's particularly useful for introspection, dynamic method invocation, and API exploration, helping developers understand and utilize the capabilities of an object.

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