datemath-parser

const parser = require('datemath-parser'); // Parse a simple expression relative to 'now' let expression1 = 'now+1h'; let timestamp1 = parser.parse(expression1); console.log(`'${expression1}' resolves to: ${new Date(timestamp1).toISOString()} (timestamp: ${timestamp1})`); // Parse an expression with rounding let expression2 = 'now/d'; // round to the beginning of the day let timestamp2 = parser.parse(expression2); console.log(`'${expression2}' resolves to: ${new Date(timestamp2).toISOString()} (timestamp: ${timestamp2})`); // Parse an expression with an explicit anchor date let expression3 = '2023-01-01||+1M/d'; // January 1st, 2023 plus one month, rounded to day let timestamp3 = parser.parse(expression3); console.log(`'${expression3}' resolves to: ${new Date(timestamp3).toISOString()} (timestamp: ${timestamp3})`); // Demonstrate parsing with a custom 'now' date and rounding up const customNow = new Date('2024-03-15T10:30:00Z'); let expression4 = 'now+2d/w'; // 2 days from customNow, rounded up to the end of the week let timestamp4 = parser.parse(expression4, customNow.getTime(), true); // Pass custom now as milliseconds, roundUp = true console.log(`'${expression4}' (with custom now ${customNow.toISOString()}) resolves to: ${new Date(timestamp4).toISOString()} (timestamp: ${timestamp4})`);