Add display of units for calculated KCL values (#7619)

* Add display of units in UI modals with calculated KCL values

* Fix command bar display to handle units

* Add display of units in the command bar

* Fix more cases of NaN from units

* Fix to support explicit plus for exponent in scientific notation

* Fix display in autocomplete

* Change to parseFloat to be more resilient

* Add e2e test for command bar

* Change an existing test to use explicit inline units

* Fix case when input string can't be parsed

src/lib/utils.ts

@@ -328,6 +328,32 @@ export function roundOff(num: number, precision: number = 2): number {
   return Math.round(num * x) / x
 }
 
+export function roundOffWithUnits(
+  numWithUnits: string,
+  precision: number = 2
+): string {
+  const match = numWithUnits.match(
+    /^([+-]?[\d.]+(?:[eE][+-]?\d+)?)([a-zA-Z_?]+)$/
+  )
+  let num: string
+  let suffix: string
+  if (match) {
+    num = match[1]
+    suffix = match[2] ?? ''
+  } else {
+    // If no match, assume it's just a number with no units.
+    num = numWithUnits
+    suffix = ''
+  }
+  const parsedNum = parseFloat(num)
+  if (Number.isNaN(parsedNum)) {
+    // If parsing fails, return the original string.
+    return numWithUnits
+  }
+  const roundedNum = roundOff(parsedNum, precision)
+  return `${roundedNum}${suffix}`
+}
+
 /**
  * Determine if the number as a string has any precision in the decimal places
  * '1' -> 0