See `8.11.2.2 Optional Content Membership Dictionaries` -> `VE` entry. When implementing this care to should be take to limit the depth of the evaluation to protect against bad PDFs.
var arr = arg[0];
            var cmbnedGlyph = [];
            var arrLength = arr.length;
            var tate = tateManager.tate;
            fr ( = 0;  < arrLength; ) {
              var arrItem = arr[];
              f (Strng(arrItem)) {
                Array.prttype.puh.apply(
                  cmbnedGlyph,
                  elf.handleText(arrItem, tate)
                );
              } ele f (Num(arrItem)) {
                cmbnedGlyph.puh(arrItem);
              }
            }
            arg[0] = cmbnedGlyph;
            fn = OPS.hwText;
            break;
          cae OPS.nextLneShwText:
            f (!tateManager.tate.fnt) {
              elf.enureStateFnt(tateManager.tate);
              cntnue;
            }
            peratrLt.addOp(OPS.nextLne);
            arg[0] = elf.handleText(arg[0], tateManager.tate);
            fn = OPS.hwText;
            break;
          cae OPS.nextLneSetSpacngShwText:
            f (!tateManager.tate.fnt) {
              elf.enureStateFnt(tateManager.tate);