汇总整理下JSON在JavaScript前后端中的使用方法，包括字符串和JSON对象的互转，JSON数组的遍历，JSON对象key值的获取，JSON内容格式化输出到文件，读取JSON内容文件转化为JSON对象等。一、JavaScript后端JSON操作方法一、JavaScript后端JSON操作方法1、JavaScript JSON字符串转JSON对象
var testStr = '{"name":"will","age":18,"hobby":"football"}'
var jsonObj = JSON.parse(testStr)

var testStr = '{"name":"will","age":18,"hobby":"football"}'
var jsonObj = JSON.parse(testStr)
2、JS JSON对象转字符串
var testObj = {
"name": 'will',
"age": '18',
"hobby": 'football'
}
var jsonStr = JSON.stringify(testObj)

var testObj = {
"name": 'will',
"age": '18',
"hobby": 'football'
}
var jsonStr = JSON.stringify(testObj)
3、JavaScript JSON数组的遍历一种是for循环遍历：
for (var l = 0; l < jsonArray.length; l++) {
var jsonItem = jsonArray[l]
}

for (var l = 0; l < jsonArray.length; l++) {
var jsonItem = jsonArray[l]
}
一种是键值遍历：
var testJSArray = [
{"number": 'one'},
{"number": "two"},
{"number": "three"},
{"number": "four"},
{"number": "five"},
{"number": "six"},
]
for(index in testJSArray){
console.log("index:" + index + "; name:" + testJSArray[index].number)
}

var testJSArray = [
{"number": 'one'},
{"number": "two"},
{"number": "three"},
{"number": "four"},
{"number": "five"},
{"number": "six"},
]
for(index in testJSArray){
console.log("index:" + index + "; name:" + testJSArray[index].number)
}
输出内容如下：
index:0; number:one
index:1; number:two
index:2; number:three
index:3; number:four
index:4; number:five
index:5; number:six
index:0; number:one
index:1; number:two
index:2; number:three
index:3; number:four
index:4; number:five
index:5; number:six4、JS JSON数组合并数组合并连接用concat方法，前端和后端都是用concat。
var testJSArray01 = [
{"name": 'one'},
{"name": "two"},
{"name": "three"},
]
var testJSArray02 = [
{"name": "four"},
{"name": "five"},
{"name": "six"},
]
var testJSONMerge = testJSArray01.concat(testJSArray02)

var testJSArray01 = [
{"name": 'one'},
{"name": "two"},
{"name": "three"},
]
var testJSArray02 = [
{"name": "four"},
{"name": "five"},
{"name": "six"},
]
var testJSONMerge = testJSArray01.concat(testJSArray02)
5、JavaScript获取JSON对象key值
var testObj = {
"name": 'will',
"age": '18',
"hobby": 'football'
}
for (var key in testObj){
console.log("key:" + key + ", value:" + testObj[key])
}

var testObj = {
"name": 'will',
"age": '18',
"hobby": 'football'
}
for (var key in testObj){
console.log("key:" + key + ", value:" + testObj[key])
}
输出内容如下：
key:name, value:will
key:age, value:18
key:hobby, value:football
key:name, value:will
key:age, value:18
key:hobby, value:football6. JS格式化输出JSON内容到文件
var writeStream = fs.createWriteStream(filePath);

return new Promise(function(resolve, reject) {
writeStream.write("写入你需要的字符串内容");
// 换行，如果是字符串中包含换行的字符，写入到.txt文件的时候并不能换行，需要输出换行符才行。
writeStream.write("\n");
// 格式化输出JSON字符串内容, JSONObj是要输出的JSON数据对象
writeStream.write(JSON.stringify(JSONObj, null, "\t") + "\n");

writeStream.end();
writeStream.on('finish', () => {
resolve(filePath);
});
});


var writeStream = fs.createWriteStream(filePath);

return new Promise(function(resolve, reject) {
writeStream.write("写入你需要的字符串内容");
// 换行，如果是字符串中包含换行的字符，写入到.txt文件的时候并不能换行，需要输出换行符才行。
writeStream.write("\n");
// 格式化输出JSON字符串内容, JSONObj是要输出的JSON数据对象
writeStream.write(JSON.stringify(JSONObj, null, "\t") + "\n");

writeStream.end();
writeStream.on('finish', () => {
resolve(filePath);
});
});

7、JavaScript读取JSON文件内容不管内容是保存成.json还是.txt，只要是合法的JSON字符串内容都可以。
var filePath = 'xxx/xxx/test.json'
var fileContent = fs.readFileSync(filePath).toString();
var fileJson = JSON.parse(fileContent);

var filePath = 'xxx/xxx/test.json'
var fileContent = fs.readFileSync(filePath).toString();
var fileJson = JSON.parse(fileContent);
二、JavaScript前端JSON操作方法二、JavaScript前端JSON操作方法1、字符串转JSON，angular.fromJson() 等价于JSON.parse()
var processInfo = angular.fromJson('{"process":[]}');

var processInfo = angular.fromJson('{"process":[]}');
2、JSON转字符串，angular.toJson() 等价于JSON.stringify()
var out = angular.toJson(jsonObj, true);

var out = angular.toJson(jsonObj, true);
3、JSON数组遍历
angular.forEach(jsonArray, function(jsonItem) {

});


angular.forEach(jsonArray, function(jsonItem) {

});

4、判断JSON对象是否含有某个Key值比如判断jsonObj这个对象是否含有“samples”这个key值
jsonObj.hasOwnProperty("samples")

jsonObj.hasOwnProperty("samples")
总结总结