Matching function name and arguments using regex

Question

I have some strings in the following pattern

'walkPath(left, down, left)'

To extract the function name alone, and the arguments in an another array, i used those regular expressions:

const str = 'walkPath(left, down, left)'

const functionNameRegex = /[a-zA-Z]*(?=\()/
console.log(str.match(functionNameRegex)) //outputs ['walkPath'] ✅✅

const argsRegex = /(?![a-zA-Z])([^,)]+)/g
console.log(str.match(argsRegex)) //outputs [ '(left', ' down', ' left' ]

the first one worked fine. In the second regex, the '(' from from '(left' should be excluded, so it should be 'left'

Hao Wu · Accepted Answer · 2020-10-14 06:07:24Z

1

Try this one:

/(?<=\((?:\s*\w+\s*,)*\s*)\w+/g

const str = 'walkPath(left, down, left)'

const functionNameRegex = /[a-zA-Z]*(?=\()/
console.log(str.match(functionNameRegex))

const argsRegex = /(?<=\((?:\s*\w+\s*,)*\s*)\w+/g
console.log(str.match(argsRegex))

It is not very restricted, if you really want to be safe, you can try:

/(?<=\w+\s*\((?:\s*\w+\s*,\s*)*\s*)\w+(?=\s*(?:\s*,\s*\w+\s*)*\))/g

answered Oct 14, 2020 at 6:07

Hao Wu

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1 Comment

Fayez Nazzal Over a year ago

I'm going to accept this one because it has less lines of code, thanks.

Tahlil · Accepted Answer · 2020-10-14 06:02:05Z

1

Use this regular expression for getting the arguments:

const argsRegex = /\(\s*([^)]+?)\s*\)/

For getting the arguments in an array:

const str = 'walkPath(left, down, left)'
const argsRegex = /\(\s*([^)]+?)\s*\)/
let res = str.match(argsRegex)
let args = res[1].split(", ")

edited Oct 14, 2020 at 6:02

answered Oct 14, 2020 at 5:39

Tahlil

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2 Comments

Fayez Nazzal Over a year ago

Thanks for the answer but it did not work, the arguments should be in an array like ['left', 'down', 'left']

Tahlil Over a year ago

@FayezNazzal I had updated the code to get the arguments in an array.

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