Tutorials

Lodash _.overEvery() Util Method

Posted in lodash Tutorial

Updated on Mar 15, 2024

By Mari Selvan

👁️ 27 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the landscape of JavaScript programming, handling multiple conditions and ensuring they all evaluate to true can be a cumbersome task. Enter Lodash, a powerful utility library that simplifies complex operations. Among its arsenal of functions lies the _.overEvery() method, a versatile tool for creating a predicate function that checks if all provided conditions are truthy.

This method streamlines conditional logic, offering concise and readable code for developers.

🧠 Understanding _.overEvery() Method

The _.overEvery() method in Lodash creates a predicate function that checks if all provided predicates return truthy values when applied to a given set of arguments. This allows developers to define multiple conditions and easily determine if they are all satisfied, simplifying complex logic.

💡 Syntax

The syntax for the _.overEvery() method is straightforward:

syntax.js

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_.overEvery([predicates])

predicates: An array of functions to be evaluated.

📝 Example

Let's dive into a simple example to illustrate the usage of the _.overEvery() method:

example.js

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const _ = require('lodash');

const isEven = num => num % 2 === 0;
const isGreaterThanTen = num => num > 10;

const isEvenAndGreaterThanTen = _.overEvery([isEven, isGreaterThanTen]);

console.log(isEvenAndGreaterThanTen(12));
// Output: true
console.log(isEvenAndGreaterThanTen(7));
// Output: false

In this example, isEvenAndGreaterThanTen is a predicate function created using _.overEvery() that checks if a number is both even and greater than ten.

🏆 Best Practices

When working with the _.overEvery() method, consider the following best practices:

Composing Predicates:

Compose simple and reusable predicates that encapsulate individual conditions. This promotes code readability and maintainability, allowing for easy modification and extension.
example.js
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```
const isPositive = num => num > 0;
const isEven = num => num % 2 === 0;
const isPositiveAndEven = _.overEvery([isPositive, isEven]);

console.log(isPositiveAndEven(6));
// Output: true
```
Parameterized Predicates:

Consider parameterizing predicates to increase their flexibility and reusability across different contexts. This enables you to create more dynamic and adaptable predicate functions.
example.js
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```
const isDivisibleBy = divisor => num => num % divisor === 0;
const isDivisibleByTwoAndThree = _.overEvery([isDivisibleBy(2), isDivisibleBy(3)]);

console.log(isDivisibleByTwoAndThree(12));
// Output: true
```

Error Handling:

Implement appropriate error handling mechanisms to gracefully handle edge cases or invalid inputs when composing predicates. This enhances the robustness and reliability of your code.

example.js

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const isString = val => typeof val === 'string';
const isLengthGreaterThanZero = val => val.length > 0;

const isNonEmptyString = _.overEvery([isString, isLengthGreaterThanZero]);

console.log(isNonEmptyString('Hello'));
// Output: true

console.log(isNonEmptyString(''));
// Output: false

📚 Use Cases

Form Validation:

_.overEvery() is ideal for form validation scenarios where multiple conditions need to be satisfied before submitting the form. By composing predicates for each validation rule, you can ensure data integrity and accuracy.

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const isRequired = val => val !== undefined && val !== null && val !== '';
const isEmail = val => /\S+@\S+\.\S+/.test(val);

const validateEmail = _.overEvery([isRequired, isEmail]);

console.log(validateEmail('example@email.com'));
// Output: true

console.log(validateEmail(''));
// Output: false

Access Control:

In access control mechanisms, _.overEvery() can be used to determine whether a user meets all required criteria for accessing a resource or performing a specific action. By combining predicates representing different access requirements, you can enforce strict access control policies.

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const isAdmin = user => user.role === 'admin';
const isVerified = user => user.status === 'verified';

const hasAdminPrivileges = _.overEvery([isAdmin, isVerified]);

console.log(hasAdminPrivileges({ role: 'admin', status: 'verified' }));
// Output: true

console.log(hasAdminPrivileges({ role: 'user', status: 'verified' }));
// Output: false

Data Filtering:

When filtering data based on multiple criteria, _.overEvery() facilitates concise and expressive code. By composing predicates representing different filter conditions, you can efficiently extract relevant subsets of data.

example.js

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const products = [
  { name: 'Laptop', price: 1200, brand: 'Dell' },
  { name: 'Smartphone', price: 800, brand: 'Samsung' },
  { name: 'Tablet', price: 400, brand: 'Apple' }
];

const filterExpensiveDellProducts = _.filter(products, _.overEvery([product => product.price > 1000, product => product.brand === 'Dell']));

console.log(filterExpensiveDellProducts);
// Output: [{ name: 'Laptop', price: 1200, brand: 'Dell' }]

🎉 Conclusion

The _.overEvery() method in Lodash empowers developers to create predicate functions that evaluate multiple conditions with ease. Whether you're implementing form validation, access control, or data filtering, this versatile utility method provides a concise and expressive solution for handling complex logic in JavaScript.

By adhering to best practices and exploring diverse use cases, you can harness the full potential of the _.overEvery() method in your Lodash projects.