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CreateFromString

function CreateFromString(const aString: String): TJSONText;

Example​

procedure ScriptEvent(var Value: variant);
var
  Factory, Parsed: TJSONText;
begin
  Factory := TJSONObject.Create;
  try
    Parsed := Factory.CreateFromString('{"status":"ready"}');
    try
      if Assigned(Parsed) then
        Value := Parsed.AsString;
    finally
      Parsed.Free;
    end;
  finally
    Factory.Free;
  end;
end;

Usage​

CreateFromString uses a required ignored receiver to parse one object or array, with a default-code-page to UTF-8 mismatch for non-ASCII input.

Additional Technical Info​

Native CreateFromString is a class function, but Velox registers it as a normal method at compile time and runtime. A script must call it through a non-nil TJSONText-typed receiver. The native code ignores the receiver, parses aString and returns a separate caller-owned object or array.

This entry has an encoding defect not present in every descendant parser. It constructs TStringStream(aString) using Delphi TEncoding.Default, which is the Windows ANSI encoding in this product, then gives the BOM-less bytes to a reader that assumes UTF-8. ASCII text is stable. Non-ASCII characters can be corrupted or rejected unless the process default code page produces the intended UTF-8 bytes. The reader also fails to validate UTF-8 continuation ranges, miscalculates four-byte sequences and reduces decoded non-BMP values to one 16-bit Char.

Empty/whitespace-only input returns nil. A scalar first value raises during the checked TJSONText cast and leaks that parsed scalar. Malformed text and numeric/conversion errors propagate; there is no TryCreate-style suppression.

Only the first value is consumed, so trailing text is ignored. Reader defects remain: literalized \uXXXX, permissive/missing array delimiters, exponent-only failure and locale-sensitive decimal conversion. The returned tree preserves duplicate object names and insertion order.

For reliable non-ASCII input, supply explicitly UTF-8/BOM-tagged bytes through CreateFromStream or use a concrete descendant path whose traced string implementation does not perform this ANSI-to-UTF-8 round trip. Always free both the receiver and non-nil result separately.

External references

Created 2026-07-15