Error while runnung command $npm start

gistfile1.txt

[05:57:49] Finished 'clean.once' after 742 ms
[05:57:49] Starting 'build.assets.dev'...
[05:57:50] Finished 'build.assets.dev' after 346 ms
[05:57:50] Starting 'build.fonts'...
[05:57:50] Finished 'build.fonts' after 147 ms
[05:57:50] Starting 'build.html_css'...
[05:57:52] Finished 'build.html_css' after 2.26 s
[05:57:52] Starting 'build.js.dev'...
src/client/app/frameworks/teamwork/services/teamwork.service.ts(5,25): error TS2307: Cannot find module 'base-64'.
[05:57:59] TypeScript: 1 semantic error
[05:57:59] TypeScript: emit succeeded (with errors)
[05:57:59] Finished 'build.js.dev' after 7.16 s
[05:57:59] Starting 'build.index.dev'...
[05:58:00] gulp-inject 6 files into index.html.
[05:58:00] gulp-inject 3 files into index.html.
(node:14730) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'replace' of undefined