Example build hardening

[p-alik]

Description

The script examples/build.sh should check if approached example (defined by $1) exists. It should use wasm-pack for todomvc example.

I'm aware about Proposal: Replace bash scripts with a Rust CLI, but as long as the script exists in the repository, it should support build of all examples.

Testing instructions

$ for d in ./*; do bn=basename $d; if [ ! -d $d ] || [ $bn = "common" ] || [ $bn = "static" ] || [ $bn = "server" ]; then continue; fi; echo ">$bn<"; ./build.sh $bn; done

I couldn't build server example for same of openssl dependencies yet.

[siku2]

I totally agree that we need to keep the examples working while #1418 is in the works. Thanks for taking the time to update the script.

There's currently another pull request which addresses similar problems in the script: #1417.
I think our best course of action is to wait until that PR is merged and then revisit this one, what do you think?

[p-alik]

I think our best course of action is to wait until that PR is merged and then revisit this one, what do you think?

Indeed, I've to wait for #1417 is merged.

[siku2]

@p-alik Happy to report that #1417 has been merged!
Most of the changes here have become redundant but there is still one thing I would love to add to Yew.
I'm talking about the check for the empty $EXAMPLE variable.

I would also like to take it one step further by adding a helpful error message if the user tries to run an example that doesn't exist. Currently the error message looks like this, which leaves a lot to be desired:

./run_example.sh: line 63: cd: yew/examples/abc: No such file or directory
[FAIL] Command: "cd "$SRCDIR/$EXAMPLE"" exited with exit code: 1

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If you don't have time to make these changes let me know, we'll just open a new issue.

[siku2]

Thanks for indulging me, @p-alik!