CouchDb中的扁平阵列

Question

我在学习CouchDb，我有个问题

我有两份文件

{
   "_id": "2a8b8edb5d47c1e9fbafd414f60023af",
   "_rev": "4-e305faba47bcb08569d225b181ba927e",
   "skills": [
       "js",
       "php"
   ],
   "type": "user",
   "age": 32
}

{
   "_id": "2a8b8edb5d47c1e9fbafd414f6002443",
   "_rev": "4-edbfaa004143fc65df823f60b7f9ee94",
   "skills": [
       "js",
       "nodejs",
       "angular"
   ],
   "type": "user",
   "age": 28
}

我想检索一个数组，比如

['js','php','nodejs','angular']

没有重复。我试过用这张地图

function(doc) {
var user = [];
for (item in doc.skills) {
  user.push(doc.skills[item]);
} 
  emit( doc.type, user);
}

我得到了

["js", "php"]
["js", "nodejs", "angular"]

我试着用这个减少

function (key, skills){
 var skill = [];
 skill.push(skills);
 return skill
}

结果是

[[["js", "nodejs", "angular"], ["js", "php"]]]

Answer 1

在减少功能中，skills是一组技能列表，因此您需要将每一项技能连接到结果中：

function(key, skills) {
  var result = [];
  var seen = {};
  skills.forEach(function(s) {
    s.forEach(function(skill) {
      if (seen[skill])
        return;
      seen[skill] = true;
      result.push(skill);
    });
  });
  return result;
}