Invalid equations with number variables

[sametaylak]

const equation = "foo__16_bar=foo__16 - bar__16"
const variableToSolve = "foo__16"
const factoredEquation = nerdamer(equation).solveFor(variableToSolve).toString()

console.log(factoredEquation) \\ => (-_bar+1)^(-1)*bar__16

I am trying to solve an equation with above example but It is creating invalid variable.

_bar should be foo__16_bar - I think It is respecting after the number part

[jiggzson]

@sametaylak, noted. That's an interesting bug. I'll look into it. Thanks for reporting.

[jiggzson]

const equation = nerdamer("foo__16_bar");
console.log(equation.toString()); //"_bar*foo__16"

Which is clearly wrong. The issue seems to be implicit multiplication. Cases such as 4_x wouldn't work anymore by treating foo__16_bar as one variable. The only solution I can think of add a setting for cases such as these. Thoughts?

[jiggzson]

@sametaylak, I forgot to @mention you.

[jiggzson]

@sametaylak, I don't normally recommend regex solutions but in this particular case I personally think it makes sense. I've moved the regex which is used to detect variables in the Settings object. Normally the regex looks like this /([\+\-\/\*]*[0-9]+)([a-z_αAβBγΓδΔϵEζZηHθΘιIκKλΛμMνNξΞoOπΠρPσΣτTυϒϕΦχXψΨωΩ]+[\+\-\/\*]*)/gi. In your case, you don't want variables to start with an underscore so we can remove it from the regex and overwrite the one that nerdamer uses. So you end up with something like this

nerdamer.set('IMPLIED_MULTIPLICATION_REGEX', /([\+\-\/\*]*[0-9]+)([a-zαAβBγΓδΔϵEζZηHθΘιIκKλΛμMνNξΞoOπΠρPσΣτTυϒϕΦχXψΨωΩ]+[\+\-\/\*]*)/gi)
const equation = nerdamer("foo__16_bar*foo__16_bar");
console.log(equation.toString()); //"foo__16_bar^2"

The underscore is ignored and treated as part of the variable. This is currently on the dev branch but will be part of version 1.1.8.