Warning: grunt.util._(...).chain(...).pluck is not a function Use --force to continue.

[konstantinj]

with grunt 1.0.1 and grunt-contrib-clean 1.0.0.

[hilnius]

I have the same error

[chocolateboy]

Packages:

• grunt v0.4.5
• grunt-cli v1.2.0
• grunt-contrib-clean v0.6.0
• grunt-legacy-util 0.2.0
• node v6.3.1
• npm 3.10.5

Error:

TypeError: grunt.util._(...).chain(...).pluck is not a function
    at Object.<anonymous> (node_modules/grunt/lib/grunt/task.js:260:55)
    at Object.<anonymous> (node_modules/grunt-contrib-clean/tasks/clean.js:53:9)
    at Object.<anonymous> (node_modules/grunt/lib/grunt/task.js:265:15)
    at Object.thisTask.fn (node_modules/grunt/lib/grunt/task.js:82:16)
    at Object.<anonymous> (node_modules/grunt/lib/util/task.js:301:30)
    at Task.runTaskFn (node_modules/grunt/lib/util/task.js:251:24)
    at Task.<anonymous> (node_modules/grunt/lib/util/task.js:300:12)
    at node_modules/grunt/lib/util/task.js:227:11
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickCallback (internal/process/next_tick.js:98:9)

node_modules/grunt/lib/grunt/task.js:260:

257    Object.defineProperty(this, 'filesSrc', {                                    
258      enumerable: true,                                                          
259      get: function() {                                                          
260        return grunt.util._(this.files).chain().pluck('src').flatten().uniq().value();
261      }.bind(this)                                                               
262    });

Cause:

lodash v4.0.0 removed pluck in favour of map (which can now take a string). On my system, node_modules/grunt-legacy-util/node_modules didn't exist (not sure why), but node_modules/lodash (v4.x) did. In the absence of a nested lodash, the top-level lodash was being used (cf. peer dependencies).

Solution:

mv node_modules old.node_modules
npm install

If the error still persists, update npm, do another fresh npm install, and ensure the following conditions are met:

• If the filesSrc getter uses pluck, node_modules/grunt-legacy-util/node_modules/lodash must be < v4.0.0.
• If the filesSrc getter uses map, node_modules/grunt-legacy-util/node_modules/lodash must be >= v4.0.0.

[chocolateboy]

Just spotted another example of this where there's a discrepancy between a package in node_modules and the tarball for that module on NPM. Specifically, the package.json for a nested dependency (glob-stream) didn't match the index.js for that package. This was occurring with npm v2.15.1 on node v0.10.48.

Reinstalling node_modules didn't help, but clearing the NPM cache and reinstalling did:

$ npm cache clean
$ rm -rf node_modules
$ npm install

[chocolateboy]

It might have something to do with this: npm/npm#4042

[sachinhasaranda]

Thanks Bro

[Ali7285]

_.chain(...).pluck is not a function