javascript - test if string has postfix (suffix)

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const hasPostfix = (text, prefix) => {
    if (prefix.length > text.length) {
        return false;
    }
    for (let i = prefix.length - 1, j = text.length - 1; i >= 0; --i, --j) {
        if (text[j] !== prefix[i]) {
            return false;
        }
    }
    return true;
};


// Usage example:

const text = 'This is example text.';

console.log(hasPostfix(text, ''));               // true
console.log(hasPostfix(text, 'text.'));          // true
console.log(hasPostfix(text, 'example text.'));  // true

console.log(hasPostfix(text, '123'));            // false
console.log(hasPostfix(text, '   '));            // false

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// Note: ES6 (ES2015) introduced String endsWith() method that lets to check if string starts with prefix.


const text = 'This is example text.';

console.log(text.endsWith(''));               // true
console.log(text.endsWith('text.'));          // true
console.log(text.endsWith('example text.'));  // true

console.log(text.endsWith('123'));            // false
console.log(text.endsWith('   '));            // false