timeout-flow/src/parseDuration.js

Fluent, composable, pauseable JavaScript timers and time control flows — plus RAF utilities for frame-based logic.

// ./src/parseDuration.js

// const timeMultipliers = Object.freeze({
//   "ms": 1,
//   "s": 1000,
//   "m": 60_000,
//   "h": 3_600_000,
// });

/** @const {!Object<string, number>} */
const timeMultipliers = Object.freeze(JSON.parse(`{
  "ms": 1,
  "s": 1000,
  "m": 60000,
  "h": 3600000
}`));

/**
 * Parses a duration string like "2s", "1.5m", "500ms" into milliseconds.
 * Also accepts raw number values (treated as ms).
 * @param {string|number} input
 * @returns {number}
 */
export function parseDuration(input) {
  if (typeof input === 'number' && Number.isFinite(input)) {
    return input;
  }

  if (typeof input !== 'string') {
    throw new TypeError(`Expected a duration string or number, got ${typeof input}`);
  }

  input = input.toLowerCase().trim();

  const match = input.match(/^(\d+(?:\.\d+)?)\s*(ms|s|m|h)$/);

  if (!match) {
    throw new Error(
      `Invalid duration format: "${input}". Expected formats like "500ms", "2s", "1.5m", or "1h".`
    );
  }

  const [, value, unit] = match;
  return parseFloat(value) * timeMultipliers[unit];
}