Provide "toCharCode" to complement String.fromCharCode

[DartBot]

This issue was originally filed by jeffbailey@google.com

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The String class provides fromCharCode, but has no matching toCharCode. The lack of this is a JavaScriptism, but it's useful to provide this for handling control characters. GWT provides this by allowing casts from char to int and generates the JS with the appropriate integer.

[DartBot]

This comment was originally written by jeffbailey@google.com

[DartBot]

This comment was originally written by fraser...@google.com

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How would this be different from the existing String.charCodeAt(int index)?

[dgrove]

Added Area-Library, Triaged labels.

[andersjohnsen]

String now have a 'charCodes' getter. I'm not sure when it was introduced, but closing issue.

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Added Fixed label.

[stevenspiel]

I believe codeUnits is now the getter

String.fromCharCodes("foo".codeUnits) == "foo"