Function collectVariables

packages/icu-messageformat-parser/manipulator.ts:164–203

* Collect all variables in an AST to Record * @param ast AST to collect variables from * @param vars Record of variable name to variable type

(
  ast: MessageFormatElement[],
  vars: Map<string, TYPE> = new Map<string, TYPE>()
)

 * @param vars Record of variable name to variable type
 */
function collectVariables(
  ast: MessageFormatElement[],
  vars: Map<string, TYPE> = new Map<string, TYPE>()
): void {
  ast.forEach(el => {
    if (
      isArgumentElement(el) ||
      isDateElement(el) ||
      isTimeElement(el) ||
      isNumberElement(el)
    ) {
      // If the variable was already registered as a plural/select, it's normal
      // for it to also appear inside as number/date/time/argument — not a conflict.
      if (vars.has(el.value)) {
        const existingType = vars.get(el.value)!
        if (
          existingType !== el.type &&
          existingType !== TYPE.plural &&
          existingType !== TYPE.select
        ) {
          throw new Error(`Variable ${el.value} has conflicting types`)
        }
      } else {
        vars.set(el.value, el.type)
      }
    }

    if (isPluralElement(el) || isSelectElement(el)) {
      vars.set(el.value, el.type)
      Object.keys(el.options).forEach(k => {
        collectVariables(el.options[k].value, vars)
      })
    }

    if (isTagElement(el)) {
      vars.set(el.value, el.type)
      collectVariables(el.children, vars)
    }
  })
}

interface IsStructurallySameResult {
  error?: Error