How to parse a date string in JavaScript
Łukasz Holeczek
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Parsing date strings in JavaScript converts text representations of dates into Date objects for calculations, formatting, and manipulation in web applications. As the creator of CoreUI, a widely used open-source UI library, I’ve implemented date parsing in countless components for calendars, date pickers, and timeline features. From my expertise, the most effective approach is using the Date constructor with ISO date strings for reliable cross-browser parsing. This method provides consistent date parsing while handling various date formats and timezone considerations for robust applications.
Use new Date() constructor to parse date strings into Date objects for manipulation.
// Parse ISO date strings (recommended)
const isoDate = new Date('2025-10-13T12:30:00Z')
const isoLocal = new Date('2025-10-13T12:30:00')
// Parse common date formats
const usFormat = new Date('10/13/2025')
const euroFormat = new Date('13/10/2025') // May not work as expected
const textFormat = new Date('October 13, 2025')
// Safe parsing with validation
function parseDate(dateString) {
const parsed = new Date(dateString)
// Check if date is valid
if (isNaN(parsed.getTime())) {
throw new Error('Invalid date string: ' + dateString)
}
return parsed
}
// Usage examples
try {
const validDate = parseDate('2025-10-13')
console.log('Parsed date:', validDate.toLocaleDateString())
const timestamp = parseDate('2025-10-13T15:30:00').getTime()
console.log('Timestamp:', timestamp)
} catch (error) {
console.error('Date parsing failed:', error.message)
}
// Parse custom format (manual approach)
function parseCustomDate(dateStr) {
// Parse "DD/MM/YYYY" format
const parts = dateStr.split('/')
if (parts.length !== 3) return null
const day = parseInt(parts[0])
const month = parseInt(parts[1]) - 1 // Month is 0-indexed
const year = parseInt(parts[2])
return new Date(year, month, day)
}
const customDate = parseCustomDate('13/10/2025')
console.log('Custom parsed:', customDate)
The Date constructor accepts ISO strings, timestamps, and various text formats but may produce inconsistent results across browsers. Always validate parsed dates using isNaN(date.getTime()) to detect invalid dates. Use ISO 8601 format (YYYY-MM-DDTHH:mm:ssZ) for reliable parsing across all environments.
Best Practice Note:
This is the same date parsing approach we use in CoreUI JavaScript components for reliable date handling. For complex date parsing requirements, consider using libraries like date-fns or moment.js for better format support and timezone handling.
