js中如何为对象添加自己定义的key和value

var key = "name"

var val = "aaa"

var o = {}

str = "o."+key+"='"+val+"'"

eval(str)

alert(o.name)

var tmpCourse = {}

_.each(course, function(value, key) {

tmpCourse[key] = value

tmpCourse[key+"test"] = value + 1

})

course = tmpCourse

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