ionic serve not starting local dev server

this is the output:

```
mymac$ ionic serve
[INFO] Starting app-scripts server: --address 0.0.0.0 --port 8100 --livereload-port 35729 - Ctrl+C to cancel
[17:42:10] watch started ...
[17:42:10] build dev started ...
[17:42:10] clean started ...
[17:42:10] clean finished in 1 ms
[17:42:10] copy started ...
[17:42:10] transpile started ...
[17:42:13] transpile finished in 2.85 s
[17:42:13] preprocess started ...
[17:42:13] deeplinks started ...
[17:42:13] deeplinks finished in 13 ms
[17:42:13] preprocess finished in 14 ms
[17:42:13] webpack started ...
[17:42:13] copy finished in 3.08 s

mymac$ ionic info

cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils : 1.9.2
ionic (Ionic CLI) : 3.9.2

local packages:

@ionic/app-scripts : 2.1.4
Ionic Framework : ionic-angular 3.6.0

System:

Node : v8.1.1
npm : 5.0.4
OS : macOS High Sierra
```
Looking for the local server on my Chrome at the address http://127.0.0.1:8100 but nothing is appearing

Start by reproducing `ionic serve` with the reported Ionic CLI, app-scripts, Node, npm, and macOS versions, then compare the output with a successful local server start. Investigate why the process stops after `webpack started` and verify that `http://127.0.0.1:8100` responds when the issue is fixed.

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