我试图了解此递归函数如何将JSON密钥转换为camelCase。有人可以在每一行中对其进行评论和/或添加说明吗?谢谢!
function toCamel(o) {
var newO, origKey, newKey, value;
if (o instanceof Array) {
return o.map(function(value) {
if (typeof value === 'object') {
value = toCamel(value);
}
return value;
});
} else {
newO = {};
for (origKey in o) {
if (o.hasOwnProperty(origKey)) {
newKey = (origKey.charAt(0).toLowerCase() + origKey.slice(1) || origKey).toString();
value = o[origKey];
if (value instanceof Array || (value !== null && value.constructor === Object)) {
value = toCamel(value);
}
newO[newKey] = value;
}
}
}
return newO;
}
答案 0 :(得分:1)
我已经注释了代码以解释正在发生的事情,请让我知道这是否没有道理!基本上,它是通过传递给它的每个项目(json)进行检查,如果它是数组或对象,则再次对其进行处理。它将密钥转换为字符串,并将第一个字符设置为小写。
// create a test json array;
var json = {
"TestArr": [
{"TestKey": 1, "ItemIDs": [0, 1, 2, 3, 4]},
{"TestKey": 2, "ItemIDs": [5, 6, 7, 8, 9]}
]
};
function toCamel(o) {
var newO, origKey, newKey, value
// if the passed parameter is an Array...
if (o instanceof Array) {
// iterate through each item in the array...
return o.map(function(value) {
// if the current item is an object...
if (typeof value === "object") {
// send the current item to this function...
// this time as an oblect
value = toCamel(value)
}
// return the current item
return value
});
// if the passed item is an object...
} else {
// create a temporary object
newO = {}
// for each key in the object
for (origKey in o) {
// check to make sure the object has a property of the current key
if (o.hasOwnProperty(origKey)) {
// convert the key to a string, then make the first character in the string lowercase
newKey = (origKey.charAt(0).toLowerCase() + origKey.slice(1) || origKey).toString()
// set the value var equal to the current key value
value = o[origKey]
// if value is an array OR the value isn't null AND its constructor is an Object...
// (ensure the value is an array or object)
if (value instanceof Array || (value !== null && value.constructor === Object)) {
// set value to this function for more processing
value = toCamel(value)
}
// set the temporary object key value to the new processed value or the original value if not an array/object
newO[newKey] = value
}
}
}
// return the finished/formatted JSON
return newO;
}
// set a variable to the value returned from the toCamel function
var test = toCamel(json);
// write out the result in the console
console.log(test);