message: WIP: Use stricter type checking in ECClass.fromJson
diff: @@ -182,10 +182,14 @@ export default abstract class ECClass extends SchemaChild implements CustomAttri
  public async fromJson(jsonObj: any): Promise<void> {
  await super.fromJson(jsonObj);
  - if (jsonObj.modifier)
  + if (jsonObj.modifier !== undefined) {
  + if (typeof(jsonObj.modifier) !== "string")
  + throw new ECObjectsError(ECObjectsStatus.InvalidECJson, `The modifier of ${this.name} is not a string type.`);
  +
  this.modifier = parseClassModifier(jsonObj.modifier);
  + }
  - if (jsonObj.baseClass) {
  + if (jsonObj.baseClass !== undefined) {
  if (typeof(jsonObj.baseClass) !== "string")
  throw new ECObjectsError(ECObjectsStatus.InvalidECJson, `The base class of ${this.name} is not a string type.`);
  