Function genericExportToArrayOrSlice

object.go:1025–1081

(o *Object, dst reflect.Value, typ reflect.Type, ctx *objectExportCtx)

}

func genericExportToArrayOrSlice(o *Object, dst reflect.Value, typ reflect.Type, ctx *objectExportCtx) (err error) {
	r := o.runtime

	if method := toMethod(r.getV(o, SymIterator)); method != nil {
		// iterable

		var values []Value
		// cannot change (append to) the slice once it's been put into the cache, so we need to know its length beforehand
		ex := r.try(func() {
			values = r.iterableToList(o, method)
		})
		if ex != nil {
			return ex
		}
		if typ.Kind() == reflect.Array {
			if dst.Len() != len(values) {
				return fmt.Errorf("cannot convert an iterable into an array, lengths mismatch (have %d, need %d)", len(values), dst.Len())
			}
		} else {
			dst.Set(reflect.MakeSlice(typ, len(values), len(values)))
		}
		ctx.putTyped(o, typ, dst.Interface())
		for i, val := range values {
			err = r.toReflectValue(val, dst.Index(i), ctx)
			if err != nil {
				return
			}
		}
	} else {
		// array-like
		var lp Value
		if _, ok := o.self.assertCallable(); !ok {
			lp = o.self.getStr("length", nil)
		}
		if lp == nil {
			return fmt.Errorf("cannot convert %v to %v: not an array or iterable", o, typ)
		}
		l := toIntStrict(toLength(lp))
		if dst.Len() != l {
			if typ.Kind() == reflect.Array {
				return fmt.Errorf("cannot convert an array-like object into an array, lengths mismatch (have %d, need %d)", l, dst.Len())
			} else {
				dst.Set(reflect.MakeSlice(typ, l, l))
			}
		}
		ctx.putTyped(o, typ, dst.Interface())
		for i := 0; i < l; i++ {
			val := nilSafe(o.self.getIdx(valueInt(i), nil))
			err = r.toReflectValue(val, dst.Index(i), ctx)
			if err != nil {
				return
			}
		}
	}

	return
}