Mean.js无法正常工作。 无法连接到MongoDB

Question

SITUATION:

I downloaded this repository: https://github.com/meanjs/mean

Followed and executed all instructions.

Did $ npm start , got the following error:

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ERROR:

Could not connect to MongoDB! { MongoError: failed to connect to server [localhost:27017] on first connect

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PS: I did install Mongodb and checked it was working with $ mongod .

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EDIT:

Full error message if I do $ npm start :

+ Important warning: config.domain is empty. It should be set to the fully qualified domain of the app.
Could not connect to MongoDB!
{ MongoError: failed to connect to server [localhost:27017] on first connect
    at Pool.<anonymous> (/Users/TLL/Desktop/Web Learn/JobBoard/node_modules/mongoose/node_modules/mongodb-core/lib/topologies/server.js:313:35)
    at emitOne (events.js:96:13)
    at Pool.emit (events.js:188:7)
    at Connection.<anonymous> (/Users/TLL/Desktop/Web Learn/JobBoard/node_modules/mongoose/node_modules/mongodb-core/lib/connection/pool.js:271:12)
    at Connection.g (events.js:291:16)
    at emitTwo (events.js:106:13)
    at Connection.emit (events.js:191:7)
    at Socket.<anonymous> (/Users/TLL/Desktop/Web Learn/JobBoard/node_modules/mongoose/node_modules/mongodb-core/lib/connection/connection.js:165:49)
    at Socket.g (events.js:291:16)
    at emitOne (events.js:96:13)
    at Socket.emit (events.js:188:7)
    at emitErrorNT (net.js:1278:8)
    at _combinedTickCallback (internal/process/next_tick.js:74:11)
    at process._tickCallback (internal/process/next_tick.js:98:9)
  name: 'MongoError',
  message: 'failed to connect to server [localhost:27017] on first connect' }
(node:5283) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): MongoError: failed to connect to server [localhost:27017] on first connect
/usr/local/bin/node[5283]: ../src/debug-agent.cc:149:void node::debugger::Agent::Stop(): Assertion `(err) == (0)' failed.
 1: node::Abort() [/usr/local/bin/node]
 2: node::RunMicrotasks(v8::FunctionCallbackInfo<v8::Value> const&) [/usr/local/bin/node]
 3: node::debugger::Agent::~Agent() [/usr/local/bin/node]
 4: node::debugger::Agent::~Agent() [/usr/local/bin/node]
 5: node::Environment::~Environment() [/usr/local/bin/node]
 6: node::Start(int, char**) [/usr/local/bin/node]
 7: start [/usr/local/bin/node]
[21:34:44] [nodemon] app crashed - waiting for file changes before starting...

Error if I do $ mongo :

MongoDB shell version v3.4.1
connecting to: mongodb://127.0.0.1:27017
2017-01-31T21:41:14.839+0100 W NETWORK  [main] Failed to connect to 127.0.0.1:27017, in(checking socket for error after poll), reason: Connection refused
2017-01-31T21:41:14.840+0100 E QUERY    [main] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed :
connect@src/mongo/shell/mongo.js:234:13
@(connect):1:6
exception: connect failed

Answer 1

Start the MongoDB instance using mongod in the command line and let it run.

Then on another terminal, run npm start . MongoDB instance should be run first.

To see the full options you can pass to mongod you can check the documentations .

Depending on your operating system, you can search to how you can put the MongoDB instance to be run at boot time, so you don't have to run it manually in a separate window.