If the parent scope property doesn't exist, it will throw a NON_ASSIGNABLE_MODEL_EXPRESSION exception. You can avoid this behavior using =? or =?attr in order to flag the property as optional.
If you want to shallow watch for changes (i.e. $watchCollection instead of $watch) you can use =* or =*attr (=*? or =*?attr if the property is optional).
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If the parent scope property doesn't exist, it will throw a NON_ASSIGNABLE_MODEL_EXPRESSION exception. You can avoid this behavior using
=?or=?attrin order to flag the property as optional.If you want to shallow watch for changes (i.e. $watchCollection instead of $watch) you can use
=*or=*attr(=*?or=*?attrif the property is optional).For two-way data binding, you can check out the portal here