webpack not found

0 info it worked if it ends with ok
1 verbose cli [ '/usr/local/bin/node', '/usr/local/bin/npm', 'run', 'build' ]
2 info using npm@3.10.6
3 info using node@v6.2.2
4 verbose run-script [ 'prebuild', 'build', 'postbuild' ]
5 info lifecycle web-driver-inspector@1.0.0~prebuild: web-driver-inspector@1.0.0
6 silly lifecycle web-driver-inspector@1.0.0~prebuild: no script for prebuild, continuing
7 info lifecycle web-driver-inspector@1.0.0~build: web-driver-inspector@1.0.0
8 verbose lifecycle web-driver-inspector@1.0.0~build: unsafe-perm in lifecycle true
9 verbose lifecycle web-driver-inspector@1.0.0~build: PATH: /usr/local/lib/node_modules/npm/bin/node-gyp-bin:/Users/shayansa/workspace/appium-1.6-beta/node_modules/appium-xcuitest-driver/WebDriverAgent/Inspector/node_modules/.bin:/Users/shayansa/workspace/appium-1.6-beta/node_modules/.bin:/usr/local/bin/:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Users/shayansa/workspace/chromium/depot_tools:/tmp/GK/bin:/Users/shayansa/workspace/chromium/depot_tools:/tmp/GK/bin:/usr/local/bin
10 verbose lifecycle web-driver-inspector@1.0.0~build: CWD: /Users/shayansa/workspace/appium-1.6-beta/node_modules/appium-xcuitest-driver/WebDriverAgent/Inspector
11 silly lifecycle web-driver-inspector@1.0.0~build: Args: [ '-c', 'webpack --progress --colors' ]
12 info lifecycle web-driver-inspector@1.0.0~build: Failed to exec build script
13 verbose stack Error: web-driver-inspector@1.0.0 build: `webpack --progress --colors`
13 verbose stack spawn ENOENT
13 verbose stack     at ChildProcess.<anonymous> (/usr/local/lib/node_modules/npm/lib/utils/spawn.js:33:16)
13 verbose stack     at emitTwo (events.js:106:13)
13 verbose stack     at ChildProcess.emit (events.js:191:7)
13 verbose stack     at maybeClose (internal/child_process.js:852:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:215:5)
14 verbose pkgid web-driver-inspector@1.0.0
15 verbose cwd /Users/shayansa/workspace/appium-1.6-beta/node_modules/appium-xcuitest-driver/WebDriverAgent/Inspector
16 error Darwin 15.6.0
17 error argv "/usr/local/bin/node" "/usr/local/bin/npm" "run" "build"
18 error node v6.2.2
19 error npm  v3.10.6
20 error file sh
21 error code ELIFECYCLE
22 error errno ENOENT
23 error syscall spawn
24 error web-driver-inspector@1.0.0 build: `webpack --progress --colors`
24 error spawn ENOENT
25 error Failed at the web-driver-inspector@1.0.0 build script 'webpack --progress --colors'.
25 error Make sure you have the latest version of node.js and npm installed.
25 error If you do, this is most likely a problem with the web-driver-inspector package,
25 error not with npm itself.
25 error Tell the author that this fails on your system:
25 error     webpack --progress --colors
25 error You can get information on how to open an issue for this project with:
25 error     npm bugs web-driver-inspector
25 error Or if that isn't available, you can get their info via:
25 error     npm owner ls web-driver-inspector
25 error There is likely additional logging output above.
26 verbose exit [ 1, true ]