Converting a math string into a JavaScript expression

Question

I am trying to convert a string into a valid JavaScript expression using JavaScript.

For example:

• 4x+2y+1z should be converted to 4*x+2*y+1*z
• 12r+6s should be converted to 12*r+6*s

I have tried to do this using a regular expression, but I was not able to do so successfully.

Answer 1

(\d+)(?=[a-z])

Try this.Replace by $1*.See demo.

http://regex101.com/r/rQ6mK9/31

Answer 2

The below code would work for your current input.

> '4x+2y+1z'.replace(/(\d)([a-z])/g, '$1*$2')
'4*x+2*y+1*z'
> '12r+6s'.replace(/(\d)([a-z])/g, '$1*$2')
'12*r+6*s'