JSFiddle - React, Tailwind, and code Playground
by Anand Jee
HTML
<div id="result"></div>
JavaScript
var data = [{"2013-01-21":1,"2013-01-22":7},{"2015-01-21":1,"2015-01-22":7}];
var result = [];
for(var m=0;m<data.length;m++){
for(var i in data[m])
result[m]=i;
}
console.log(result);
$('#result').html(JSON.stringify(result));