Ternary operator, or the operation of the magical

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var data2 = typeof data === 'function' ? getData(data) : data || {};

analysis:

• Directly or operator-assignment will complain

var data2 = temp || 2;
console.log(data2); // 报错：Uncaught ReferenceError: temp is not defined at <anonymous>:1:13

Ternary operator in use:

• data for the object

var data = {
  name: 'robert'
}
console.log(data2) // data || {} 得 {name: 'robert'}

• data as a function of 

var data = function (obj) {
  return obj.name
}
console.log(data2) // getData(data)

• data not declared

console.log(data2) // data || {} 得 {}