---
id: 646d448479c8fdc8dcec868c
title: Step 83
challengeType: 0
dashedName: step-83
---
# --description--
Declare a `functionCall` variable, and assign it this regular expression: `/([a-z0-9]*)\(([0-9., ]*)\)(?!.*\()/i`
This expression will look for function calls like `sum(1, 4)`.
# --hints--
You should declare a `functionCall` variable.
```js
assert.match(code, /const\s+applyFunction\s*=\s*(\(\s*str\s*\)|str)\s*=>\s*\{\s*const\s+noHigh\s*=\s*highPrecedence\(\s*str\s*\)\s*;?\s*const\s+infix\s*=\s*\/\(\[(?:\\d\.|\.\\d)\]\+\)\(\[(?:\+-|-\+)\]\)\(\[(?:\\d\.|\.\\d)\]\+\)\/\s*;?\s*const\s+str2\s*=\s*infixEval\(\s*noHigh\s*,\s*infix\s*\)\s*;?\s*(?:const|let|var)\s+functionCall\s*=/);
```
You should use `const` to declare your `functionCall` variable.
```js
assert.match(code, /const\s+applyFunction\s*=\s*(\(\s*str\s*\)|str)\s*=>\s*\{\s*const\s+noHigh\s*=\s*highPrecedence\(\s*str\s*\)\s*;?\s*const\s+infix\s*=\s*\/\(\[(?:\\d\.|\.\\d)\]\+\)\(\[(?:\+-|-\+)\]\)\(\[(?:\\d\.|\.\\d)\]\+\)\/\s*;?\s*const\s+str2\s*=\s*infixEval\(\s*noHigh\s*,\s*infix\s*\)\s*;?\s*const\s+functionCall\s*=/);
```
You should assign `functionCall` the provided regular expression.
```js
assert.match(code, /const\s+applyFunction\s*=\s*(\(\s*str\s*\)|str)\s*=>\s*\{\s*const\s+noHigh\s*=\s*highPrecedence\(\s*str\s*\)\s*;?\s*const\s+infix\s*=\s*\/\(\[(?:\\d\.|\.\\d)\]\+\)\(\[(?:\+-|-\+)\]\)\(\[(?:\\d\.|\.\\d)\]\+\)\/\s*;?\s*const\s+str2\s*=\s*infixEval\(\s*noHigh\s*\,\s*infix\s*\)\s*;?\s*const\s+functionCall\s*=\s*\/\(\[a-z0-9\]\*\)\\\(\(\[0-9\., \]\*\)\\\)\(\?!\.\*\\\(\)\/i/);
```
# --seed--
## --seed-contents--
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