javascript - What is the JS pattern to get unique elements from nested array? -


i have following result mongodb.aggregate:

[{    _id: objectid(1),     _author: objectid(2),    comments: [       {          _author: objectid(2),          text: '...'       },       {          _author: objectid(3),          text: '...1'       },       {          _author: objectid(3),          text: '...2'       }...    ] }...]

i need unique authors _author field elemnts (including nested):

var uniqauthors = magicfunction(result) // [objectid(2), objectid(3)] ;

what best , compact way make pure js?

array.prototype.reduce can you:

var unique = result[0].comments.reduce(function(uniqueauthors, comment) {   if (uniqueauthors.indexof(comment._author) === -1) {      uniqueauthors.push(comment._author);   }   return uniqueauthors; }, []); //verify author document if (unique.indexof(result[0]._author) === -1) {    uniqueauthors.push(result[0]._author); }

Comments

Post a Comment

Popular posts from this blog

php - Wordpress website dashboard page or post editor content is not showing but front end data is showing properly -

Image
recently have uploaded wordpress site onto server. have uploaded wordpress site in sub-folder under root folder ../root(domain root folder)/wordpress (where host wordpress folder). now problem content data in page or post in dashboard of wordpress admin panel not showing - see image. but data showing in front view - see image. if not browser cache issue , not issue happened tinymce editor during upgrade; try add config file: define('concatenate_scripts', false);
Read more

How to get the ip address of VM and use it to configure SSH connection dynamically in Ansible -

i trying ip address of vm , trying use establish ssh vm. following script: --- - hosts: localhost become: yes connection: local gather_facts: false serial: 1 vars_files: - createvmvars.yml tasks: - name: gathering vm info. vsphere_guest: vcenter_hostname: "{{vcenter_hostname}}" username: "{{vcenter_username}}" password: "{{vcenter_password}}" guest: "{{guest_name}}" vmware_guest_facts: yes register: var - debug: msg="{{var.ansible_facts.hw_eth0.ipaddresses[0]}}" - name: establishing ssh connection. script: /home/shasha/devops/scripts/ssh_configure.sh "{{var.ansible_facts.hw_eth0.ipaddresses[0]}}" following content of ssh_configure.sh : #!/bin/sh ssh-keygen -t rsa ssh-copy-id $1 but when running playbook, getting following error while executing third task: error! 'var' undefined but debug module(second task) printin
Read more

javascript - Get parameter of GET request -

i make request: createxhrrequest( "get", fileurl, function( err, response ) { if( err ) { alert( "error get!" ); } alert(response); }); and full response: { "status" : "ok", "message" : "jvberi0xljqkjdduxdgkmy how can jvberi0xlj ? i try response.message , response["message"]. nothing works. just simple access this: var json = json.parse(response); json.message
Read more