从javascript中的文件读取json

Question

I have this json file:

test.json :

{"rows" : [
  {"key": "value"},
  {"key": "value"}
 ]
}

I tried this code to read it:

var json = require('test.json');
for (var row in json.rows) {
    console.log(row.key);
}

it prints:

/usr/local/bin/node json-parser.js
undefined
undefined

What am I doing wrong?

Answer 1

Where row is the variable holding property name not the object, so you need to retrieve it using the property name ( Refer : for...in loop documentation ). In your case it will be the index of array. There is no need to use for...in iterator here, a simple for loop is enough.

for (var row in json.rows) {
  console.log(json.rows[row].key);
}

 var json = { "rows": [{ "key": "value" }, { "key": "value" }] }; for (var row in json.rows) { console.log(json.rows[row].key); } 

---

With a simple for loop

for (var i=0;i < json.rows.length; i++) {
  console.log(json.rows[i].key);
}

 var json = { "rows": [{ "key": "value" }, { "key": "value" }] }; for (var i = 0; i < json.rows.length; i++) { console.log(json.rows[i].key); } 

---

Since the property holds an array use Array#forEach method to iterate.

json.rows.forEach(function(v){
  console.log(v.key);
}

 var json = { "rows": [{ "key": "value" }, { "key": "value" }] }; json.rows.forEach(function(v) { console.log(v.key); })