josdejong/mathjs

TS regression: Narrowing of MathNodes by type

Aperta

#2810 aperta il 13 ott 2022

 (23 commenti) (0 reazioni) (0 assegnatari)JavaScript (1314 fork)batch import
bughelp wantedtypescript

Metriche repository

Star
 (15.065 stelle)
Metriche merge PR
 (Metriche PR in attesa)

Descrizione

Describe the bug Prior to v11.3 (not sure how far back, but certainly at least 10), MathNode would be narrowed based on its type property:

const doStuffWithMathNode(node: MathNode) => {
  if (node.type === 'FunctionAssignmentNode) {
    // now TS knows that node is a FunctionAssignmentNode and lets you access associated props
    // like node.params
  }
  // back to being a wider MathNode
}

To Reproduce

Guida contributor