Function _ensureNode

src/function/algebra/simplifyConstant.js:135–140

(thing)

  })

  function _ensureNode (thing) {
    if (isNode(thing)) {
      return thing
    }
    return _toNode(thing)
  }

  // convert a number to a fraction only if it can be expressed exactly,
  // and when both numerator and denominator are small enough