diff options
Diffstat (limited to 'fastdom.js')
| -rw-r--r-- | fastdom.js | 45 |
1 files changed, 41 insertions, 4 deletions
@@ -45,6 +45,7 @@ function FastDom() { } FastDom.prototype = { + version: 1, constructor: FastDom, /** @@ -231,12 +232,48 @@ function mixin(target, source) { } } -// There should never be more than -// one instance of `FastDom` in an app -var exports = win.fastdom = (win.fastdom || new FastDom()); // jshint ignore:line +/** + * Exports + * + * In order for fastdom to work in the most + * performant way it must be a global singleton + * within each app. If two fastdom's are operating + * at the same time, they can collide and force + * additional reflows. + * + * To circumvent this we: + * + * 1. Check for any pre-existing `fastdom` + * 2. Test if the major versions are the same + * 3. If compatible, we export the existing instance + * 4. If not compatible we console.warn and create a new instance + * + * This assumes that instances of the same semver + * major version have the same public API. Any + * minor or patch versions are disregarded. + * The first fastdom loaded wins. + */ -// Expose to CJS & AMD +var exports = (function() { + var existing = win['fastdom'] || win['__fastdom__']; + + if (existing) { + var version = existing.version || (existing.defer ? 0 : 1); + var compatible = version === FastDom.prototype.version; + var exports = compatible ? existing : new FastDom(); + if (compatible) return existing; + console.warn('[fastdom] Multiple incompatible versions detected (this could impact performance)'); + } + + return new FastDom(); +})(); + +// Expose to CJS, AMD or window if ((typeof define)[0] == 'f') define(function() { return exports; }); else if ((typeof module)[0] == 'o') module.exports = exports; +else win['fastdom'] = exports; + +// Expose 'hidden' global +win['__fastdom__'] = exports; })( window || this); |