Use a view to get the same suffix like maindomain name - mapreduce

Question

I have some documents, how can use a view to get the document which have the same domain name for their email address. like all the document with #gmail.com or #yahoo.com, if endkey can get that results?
Here is what I wrote a view on map, But I do not think this is good idea
function(doc) {
for (var i in doc.emails) {
if (doc.emails[i].emailAddress.toLowerCase().indexOf("#yahoo.ibm.com")!=-1) {
emit(doc.emails[i].emailAddress.toLowerCase(), doc);
}
}
}
}

Answer 1

To make things clear, the endkey parameter is not looking for a suffix. Startkey and endkey are like the limits of keys to get. For example, you could get the document with the id 1 to the id 10 startkey="1"&endkey="10" .
In your case, you want to make a view that will group your documents by their domain name. I created a design document with a byDomain view. The mapping function looks like this :
function(doc){
if(doc.email){ //I used the document's property email for my view.
//Now, we will emit an array key. The first value will be the domain.
//To get the domain, we split the string with the character '#' and we take what comes after.
//Feel free to add more validations
//The second key will be the document id. We don't emit any values. It's faster to simply add
//the includes_docs query parameter.
emit([doc.email.split('#')[1],doc._id]);
}
}
Let's query all my documents to show you what I have
Request : http://localhost:5984/test/_all_docs?include_docs=true
Response:
{"total_rows":4,"offset":0,"rows":[
{"id":"7f34ec3b9332ab4e555bfca202000e5f","key":"7f34ec3b9332ab4e555bfca202000e5f","value":{"rev":"1-c84cf3bf33e1d853f99a4a5cb0a4af74"},"doc":{"_id":"7f34ec3b9332ab4e555bfca202000e5f","_rev":"1-c84cf3bf33e1d853f99a4a5cb0a4af74","email":"steve#gmail.com"}},
{"id":"7f34ec3b9332ab4e555bfca202001101","key":"7f34ec3b9332ab4e555bfca202001101","value":{"rev":"1-53a8a9f2a24d812fe3c98ad0fe020197"},"doc":{"_id":"7f34ec3b9332ab4e555bfca202001101","_rev":"1-53a8a9f2a24d812fe3c98ad0fe020197","email":"foo#example.com"}},
{"id":"7f34ec3b9332ab4e555bfca202001b02","key":"7f34ec3b9332ab4e555bfca202001b02","value":{"rev":"1-cccec02fe7172fb637ac430f0dd25fa2"},"doc":{"_id":"7f34ec3b9332ab4e555bfca202001b02","_rev":"1-cccec02fe7172fb637ac430f0dd25fa2","email":"bar#gmail.com"}},
{"id":"_design/emails","key":"_design/emails","value":{"rev":"4-76785063c7dbeec96c495db76a8faded"},"doc":{"_id":"_design/emails","_rev":"4-76785063c7dbeec96c495db76a8faded","views":{"byDomain":{"map":"\t\tfunction(doc){\n\t\t\tif(doc.email){ //I used the document's property email for my view.\n\t\t\t\t//Now, we will emit an array key. The first value will be the domain.\n\t\t\t\t//To get the domain, we split the string with the character '#' and we take what comes after.\n\t\t\t\t//Feel free to add more validations\n\t\t\t\t//The second key will be the document id. We don't emit any values. It's faster to simply add\n\t\t\t\t//the includes_docs query parameter.\n\t\t\t\temit([doc.email.split('#')[1],doc._id]); \n\t\t\t}\n\t\t}"}},"language":"javascript"}}
]}
As you can see, I got few minimalist documents with the property "email" set.
Let's query my view without any parameters
Request : http://localhost:5984/test/_design/emails/_view/byDomain
Response :
{"total_rows":3,"offset":0,"rows":[
{"id":"7f34ec3b9332ab4e555bfca202001101","key":["example.com","7f34ec3b9332ab4e555bfca202001101"],"value":null},
{"id":"7f34ec3b9332ab4e555bfca202000e5f","key":["gmail.com","7f34ec3b9332ab4e555bfca202000e5f"],"value":null},
{"id":"7f34ec3b9332ab4e555bfca202001b02","key":["gmail.com","7f34ec3b9332ab4e555bfca202001b02"],"value":null}
]}
Let's query only documents with that have the gmail.com domain.
Request : http://localhost:5984/test/_design/emails/_view/byDomain?startkey=["gmail.com"]&endkey=["gmail.com","\ufff0"]
Result :
{"total_rows":3,"offset":1,"rows":[
{"id":"7f34ec3b9332ab4e555bfca202000e5f","key":["gmail.com","7f34ec3b9332ab4e555bfca202000e5f"],"value":null},
{"id":"7f34ec3b9332ab4e555bfca202001b02","key":["gmail.com","7f34ec3b9332ab4e555bfca202001b02"],"value":null}
]}

Answer 2

You can just use a simple map function for this:
function (doc) {
var domain = doc.email.split('#').pop();
// this logic is fairly hack-ish, you may want to be more sophisticated
emit(domain);
}
Then you can simply pass key=gmail.com to get the results you want from the view. I would also add include_docs=true instead of emitting the entire document as your value.
You can read more about views in the official CouchDB docs.