I have a function
const output = {}
sites.forEach(obj=>{
const ids = obj.ids
if(ids && ids.length>0){
ids.forEach(id=>{
if(!output[id]){
output[id] = []
}
output[id].push(obj.url);
});
}
});
fs.writeFileSync('cleanedData.json', JSON.stringify(output));
that takes data such as:
{
url: "www.site.com",
ids: ["F20", "C10", "C05"]
},
{
url: "www.site.com/something",
ids: ["F20", "C05", "C10"]
},
{
url: "www.site.com/somethingelse",
ids: ["F20", "C12", "C05"]
}
and transforms it so that I have a list of all ids and all urls with that id:
{
"F20": [
"www.site.com",
"www.site.com/something",
"www.site.com/somethingelse"
]
}, {
"C10": [
"www.site.com",
"www.site.com/something"
]
}, {
"C12": [
"www.site.com/somethingelse"
]
}, {
"C05": [
"www.site.com",
"www.site.com/something",
"www.site.com/somethingelse"
]
}
I'm able to get a count of each id's array length with
console.log(Object.values(output).map(id => id.length))
But can't figure out how to include that as part of the forEach, so that I have a key/value in each object that shows the length of the array.
Use nested objects in the output, and give it a length property that you increment when you push onto the array.
const sites = [{
url: "www.site.com",
ids: ["F20", "C10", "C05"]
},
{
url: "www.site.com/something",
ids: ["F20", "C05", "C10"]
},
{
url: "www.site.com/somethingelse",
ids: ["F20", "C12", "C05"]
}
];
const output = {};
sites.forEach(obj => {
const ids = obj.ids
if (ids && ids.length > 0) {
ids.forEach(id => {
if (!output[id]) {
output[id] = {length: 0, urls: []}
}
output[id].urls.push(obj.url);
output[id].length++;
});
}
});
console.log(output);You can use Array.prototype.reduce() combined with Array.prototype.forEach():
const sites = [{url: "www.site.com",ids: ["F20", "C10", "C05"]},{url: "www.site.com/something",ids: ["F20", "C05", "C10"]},{url: "www.site.com/somethingelse",ids: ["F20", "C12", "C05"]}]
const output = sites.reduce((a, { url, ids }) => {
ids.forEach(id => {
a[id] = a[id] || { length: 0, urls: [] }
a[id].length += 1
a[id].urls.push(url)
})
return a
}, {})
console.log(output)