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@syoichi
Last active November 14, 2016 15:33
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nodeObserver - utility function for MutationObserver
/* example
nodeObserver(function log(info) {
console.log(info);
info.options.observer.disconnect();
}, {
target: document,
childList: true,
subtree: true,
addOnly: true
});
document.body.appendChild(document.createElement('div'));
document.body.insertAdjacentHTML('BeforeEnd', '<div></div><div></div>');
document.body.removeChild(document.body.lastElementChild);
setTimeout(function () {
document.body.appendChild(document.createElement('div'));
}, 1000);
// -> log 3 info, not 5 info.
*/
/**
* utility function for MutationObserver
* @version 3.0.0
* @link https://dom.spec.whatwg.org/#mutation-observers
* @param {Function} callback
* @param {Object} options
* @returns {Object} options
*/
function nodeObserver(callback, options) {
let hasOnly = options.addOnly || options.removeOnly;
let nodesType = options.addOnly ? 'addedNodes' : 'removedNodes';
let observer = new MutationObserver(mutations => {
for (let record of mutations) {
let nodes = record.type === 'childList' && hasOnly ?
record[nodesType] :
[null];
for (let node of nodes) {
callback({node, record, options});
}
}
});
observer.observe(options.target, options);
return Object.assign(options, {observer, callback});
}
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