11th work3

Arrow function restore
var materials = [
'Hydrogen',

'Helium',

'Lithium',

'Beryllium'
];

console.log(materials.map(material => material.length));
写出这个的标准函数形式，就像下面这个形式一样
var selected = allJobs.filter(function (job) {
return job.isSelected();
});

var selected = allJobs.filter(job => job.isSelected());

先画饼。