chrono-swift

chrono-swift is a Swift wrapper for Wanasit Tanakitrungruang’s excellent chrono.js natural language date parser. chrono-swift lets you use chrono.js for your iOS, macOS, or tvOS apps, all while working with native Swift and Foundation data types. No need to deal with any of JavaScript’s silliness.

chrono-swift, (referred to as “Chrono” from here onwards), extracts date information from natural language phrases like “Remind me in 2 days” or “Meet me this Saturday from 3-4 PM” and returns Swift Date or DateInterval values.

Setup

Just add the “Chrono” folder located at the root of the repo to your Xcode project.

Usage

Using Chrono is easy. First, create an instance of the Chrono singleton:

let chrono = Chrono.shared

Extract Date

To extract a date from a natural language phrase, simply pass in the phrase to Chrono’s dateFrom(naturalLanguageString:) method. Here, the reference date is assumed to be the current system date.

let date = chrono.dateFrom(naturalLanguageString: "Remind me in 2 days")
// If today is November 17th, 2016, `date` will be November 19th, 2016

If you want to use a different date as the reference date, use dateFrom(naturalLanguageString:referenceDate:)

Extract Date Interval

To extract a date interval from a natural language phrase, pass in the phrase to Chrono’s dateIntervalFrom(naturalLanguageString:) method. Again, the reference date is assumed to be the current system date here.

let dateInterval = chrono.dateIntervalFrom(naturalLanguageString: "Meet me this Saturday from 3-4 PM")
// If today is November 17th, 2016, `dateInterval` will be November 19th, 2016 3:00 PM - November 19th, 2016 4:00 PM

If you want to use a different date as the reference date, use dateIntervalFrom(naturalLanguageString:referenceDate:)

Detailed Parsed Results

You can also get more detailed parsed results using Chrono’s parsedResultsFrom(naturalLanguageString:) method.

let result = chrono.parsedResultsFrom(naturalLanguageString: "I have an appointment tomorrow from 10 to 11 AM", referenceDate: nil) // If referenceDate is nil, it is assumed to be the current system date.
print(results)

result will be a special struct of type ChronoParsedResult. This struct contains several member variables that describe the parsed result. In this case, the struct will look like this:

inputString: I have an appointment tomorrow from 10 to 11 AM
indexOfStartingCharacterOfTimePhrase: 22
timePhrase: tomorrow from 10 to 11 AM
ignoredText: I have an appointment 
referenceDate: November 17, 2016 at 8:18:14 PM CST
startDate: November 18, 2016 at 10:00:00 AM CST
endDate: November 18, 2016 at 11:00:00 AM CST
dateInterval: November 18, 2016, 10:00:00 AM CST - 11:00:00 AM CST

Sample Project

Under the “Sample Apps” folder is a sample Xcode project with iOS, macOS, and tvOS targets.