Parsing JSON files in nodejs - node.js

Question

I want to parse this JSON data to a file like this :
JSON
{
"nodes": [
{"id": 1, "name" : "a", "radius" :0.5, "angle" : 2.64159265359},
{"id": 2, "name" : "b", "radius" : 0.6, "angle" : 3.64159265359}
],
"links": [
{"source": "a", "target": "b", "delay": "10ms"}
]
}
File :
[nodes]
a: _ radius=0.5 angle=2.64159265359
b: _ radius=0.6 angle=3.64159265359
[links]
a:b delay=10ms
So far my code is just reading the JSON file
const fs = require('fs');
data = JSON.parse(fs.readFileSync("topo.json","utf-8"));
for (node in data)
{
for (link in data[node])
{
console.log(data[node][link]);
}
}
How can I get those values saved and create a new file having those values in them ?

Answer 1

You did not specify what file type you want to use, so I went with a simple .txt file.
The only small Issue with the code posted, is that these are arrays, so you have to loop a bit differently over them. Apart from that simply write the data into placeholders in your format string and append it to a global object that will be written to the file. Then you should be good to like that:
const fs = require('fs');
const data = JSON.parse(fs.readFileSync('topo.json','utf-8'));
let textFileContent = '';
textFileContent += '[nodes]\n';
data.nodes.forEach(node => {
textFileContent += `${node.name}: _ radius=${node.radius} angle=${node.angle}\n`;
});
textFileContent += '[links]\n';
data.links.forEach(link => {
textFileContent += `${link.source}:${link.target} delay=${link.delay}\n`;
});
fs.writeFile('parsed.txt', textFileContent, function(err) {
if(err) {
return console.log(err);
}
});
Note that this could probably be done more elegant and it won`t scale very well, if your JSON is more complex, than whats shown in the sample...