ES6 modules

[oliviertassinari]

It would be great to support it. For now, the best way I see to use this module is by copy-pasting the content into one of my files.

[ebidel]

Does import Metric from 'appmetrics.js' not work? I guess I need an export default?

[oliviertassinari]

I have noticed several things to do to make it work:

• Export the Metric class: export default Metric;
• Point the main section of the package.json toward the right entry point. Right now, it's pointing toward "main": "./src/appmetrics.js". But it's very common to ignore the node_modules when using babel.

Here is the version I'm using:

``` js // @flow weak import warning from 'warning'; // Allow to remove the assertion code from production const start = new WeakMap(); const end = new WeakMap(); // Not sure why weren't private method. /** * True if the the browser supports the Navigation Timing API. * @type {boolean} */ function supportsPerfNow() { return window.performance && window.performance.now; } /** * True if the the browser supports the User Timing API. * @type {boolean} */ function supportsPerfMark() { return window.performance && window.performance.mark; } // Inspired by https://github.com/ebidel/appmetrics.js class Metric { /** * Returns the duration of the timing metric or -1 if there a measurement has * not been made. * @type {number} */ get duration() { let duration; if (supportsPerfNow()) { duration = end.get(this) - start.get(this); } // Use User Timing API results if available, otherwise return // window.performance.now() fallback. if (supportsPerfMark()) { // Note: this assumes the user has made only one measurement for the given // name. Return the first one found. const entry = window.performance.getEntriesByName(this.name)[0]; if (entry && entry.entryType !== 'measure') { duration = entry.duration; } } return duration || -1; } name = ''; /** * @param {string} name A name for the metric. */ constructor(name) { warning(name, 'Please provide a metric name'); // Simplify it, I don't want to crash when the performance API is not supported. this.name = name; } /** * Call to begin a measurement. * @return {Metric} Instance of this object. */ start() { if (start.get(this)) { warning(false, 'Recording already started.'); return this; } if (supportsPerfNow()) { start.set(this, window.performance.now()); } // Support: developer.mozilla.org/en-US/docs/Web/API/Performance/mark if (supportsPerfMark()) { window.performance.mark(`mark_${this.name}_start`); } return this; } /** * Call to end a measurement. * @return {Metric} Instance of this object. */ end() { if (end.get(this)) { warning(false, 'Recording already stopped.'); return this; } if (supportsPerfNow()) { end.set(this, window.performance.now()); } // Support: developer.mozilla.org/en-US/docs/Web/API/Performance/mark if (supportsPerfMark()) { const startMark = `mark_${this.name}_start`; const endMark = `mark_${this.name}_end`; window.performance.mark(endMark); window.performance.measure(this.name, startMark, endMark); } return this; } // Remove sendToAnalytics as I'm using different API based on the platfrom : cordova / browser. } export default Metric; ```

[oliviertassinari]

I have been publishing that among other tools for my needs under browser-metrics.

[ebidel]

Any interest in sending a pr?