duktape/website/api/duk_next.yaml

name: duk_next

proto: |
  duk_bool_t duk_next(duk_context *ctx, duk_idx_t enum_index, duk_bool_t get_value);

stack: |
  [ ... enum! ... ] -> [ ... enum! ... ]             (if enum empty; function returns zero)
  [ ... enum! ... ] -> [ ... enum! ... key! ]        (if enum not empty and get_value == 0; function returns non-zero)
  [ ... enum! ... ] -> [ ... enum! ... key! value! ] (if enum not empty and get_value != 0; function returns non-zero)

summary: |
  <p>Get the next key (and optionally value) from an enumerator created with
  <code><a href="#duk_enum">duk_enum()</a></code>.  If the enumeration has been
  exhausted, nothing is pushed to the stack and the function returns zero.
  Otherwise the key is pushed to the stack, followed by the value if
  <code>get_value</code> is non-zero, and the function returns non-zero.
  </p>

  <p>Note that getting the value may invoke a getter which may have arbitrary
  side effects (and may throw an error).</p>

example: |
  while (duk_next(ctx, enum_idx, 1)) {
      printf("key=%s, value=%s\n", duk_to_string(ctx, -2), duk_to_string(ctx, -1));
      duk_pop_2(ctx);
  }

tags:
  - object
  - property

seealso:
  - duk_enum

introduced: 1.0.0