如何使用Closure Compiler优化Javascript并保留函数名称？

Question

I have a javascript-file (lib.js) and I want to use some of the functions in an web page but I don't want to load the full lib.js.

However, I have not figured out how to do what I want. I want to use command line.

lib.js

function dog() {
    return 'Fido';
}

function famous_human() {
    return 'Winston';
}

function human() {
    return famous_human();
}

code-calling-functions-in-lib.js

alert(human());

Desired result, lib-compiled.js

function a() {return 'Winston';}function human() {return a();}

• Function dog is removed since I don't use it.
• Function famous_human is is optimized.
• Function human has its original name since I want to call it from other code.
• No code from code-calling-functions-in-lib.js

.

java -jar compiler.jar --compilation_level ADVANCED_OPTIMIZATIONS --js lib.js --XXXXXXXX code-calling-functions-in-lib.js --js_output_file lib-compiled.js    

Is there a simple answer to my question?

Answer 1

You can export human:

function human() {
    return famous_human();
}

window['human'] = human;

More information on exports

Since exporting symbols blocks dead-code elimination, a best practice is to keep the project-specific exports in a separate file and not included in your library.

Example

Library Source - liba.js

function dog() {
  return 'Fido';
}

function famous_human() {
  return 'Winston';
}

function human() {
  return famous_human();
}

Project Specific Exports - project_exports.js

window['human'] = human;

Compile command

java -jar compiler.jar \
  --compilation_level ADVANCED_OPTIMIZATIONS \
  --js liba.js \
  --js project_exports.js \
  --js project_source.js \
  --js_output_file project_compiled.js