Uncaught ReferenceError: _ is not defined

[xuye]

when i import angular-underscore.js file and inject to angular module, it will have a error like this:
Uncaught ReferenceError: _ is not defined in angular-underscore.js line 157.
have any suggestion?

[floydwch]

It seems you not import the underscore or lodash first.

[raynoppe]

I get the same error my code with import sequins

var MetronicApp = angular.module("MetronicApp", [
"angular-underscore",
"ui.router",
"ui.bootstrap",
"oc.lazyLoad",
"ngSanitize",
"angular-websql",
"checklist-model",
"ui.sortable"
]);

js file loaded successfully show fine in network.