EN
JavaScript - get function argument names
7 points
In this short article we would like to show sinmple way how to get function argument names in JavaScript.
Note: be careful, transpilation and compression may change argument names.
Practical example:
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const functionExpression = /^(?:function(?:\s+[^\(]+)?)?\(\s*([^\)]*\s*)\)/i;2
const delimiterExpression = /,\s*/i;3
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const getArgumentNames = action => {5
const code = action.toString();6
const matching = functionExpression.exec(code);7
if (matching) {8
const group = matching[1];9
return group.split(delimiterExpression);10
}11
return [];12
};13
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// Usage example:16
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function myFunction1(arg1) {18
console.log('myFunction1 called...');19
}20
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const myFunction2 = function FunctionName(arg1, arg2) {22
console.log('FunctionName called...');23
};24
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const myFunction3 = function(arg1, arg2, arg3) {26
console.log('myFunction3 called...');27
};28
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const myFunction4 = (arg1, arg2, arg3, arg4) => {30
console.log('myFunction3 called...');31
};32
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console.log(getArgumentNames(myFunction1));34
console.log(getArgumentNames(myFunction2));35
console.log(getArgumentNames(myFunction3));36
console.log(getArgumentNames(myFunction4));Note: above example code doesn't wor for code with placed comments inside function declaration (e.g.
function /* note ... */ myFunction() { }). It is necessary to do some preprocessing to remove comments.
