fraction with unary minus operator multiplying a variable produce a different tree

[mt4c]

console.log(JSON.stringify(math.parse('4/3x')));

results in

{"mathjs":"OperatorNode","op":"*","fn":"multiply","args":[{"mathjs":"OperatorNode","op":"/","fn":"divide","args":[{"mathjs":"ConstantNode","value":4},{"mathjs":"ConstantNode","value":3}],"implicit":false},{"mathjs":"SymbolNode","name":"x"}],"implicit":true}

console.log(JSON.stringify(math.parse('+4/3x')));
console.log(JSON.stringify(math.parse('-4/3x')));

results in

{"mathjs":"OperatorNode","op":"/","fn":"divide","args":[{"mathjs":"OperatorNode","op":"+","fn":"unaryPlus","args":[{"mathjs":"ConstantNode","value":4}],"implicit":false},{"mathjs":"OperatorNode","op":"*","fn":"multiply","args":[{"mathjs":"ConstantNode","value":3},{"mathjs":"SymbolNode","name":"x"}],"implicit":true}],"implicit":false}

{"mathjs":"OperatorNode","op":"/","fn":"divide","args":[{"mathjs":"OperatorNode","op":"-","fn":"unaryMinus","args":[{"mathjs":"ConstantNode","value":4}],"implicit":false},{"mathjs":"OperatorNode","op":"*","fn":"multiply","args":[{"mathjs":"ConstantNode","value":3},{"mathjs":"SymbolNode","name":"x"}],"implicit":true}],"implicit":false}

the first expression was parsed as (4/3)x

the next expressions were parsed as 4/(3x) and -4/(3x)

Why do the unary operators make the differences

[cshaa]

This is a known bug in the parser, see #1431.

[josdejong]

Let's continue any discussion in #1431. Any help solving the issue is very welcome.