How to use the pegjs/lib/compiler/opcodes.IF function in pegjs

"        case " + op.APPEND + ":", // APPEND
      "          stack[stack.length - 2].push(stack.pop());",
      "          ip++;",
      "          break;",
      "",
      "        case " + op.WRAP + ":", // WRAP n
      "          stack.push(stack.splice(stack.length - bc[ip + 1], bc[ip + 1]));",
      "          ip += 2;",
      "          break;",
      "",
      "        case " + op.TEXT + ":", // TEXT
      "          stack.push(input.substring(stack.pop(), peg$currPos));",
      "          ip++;",
      "          break;",
      "",
      "        case " + op.IF + ":", // IF t, f
      indent10(generateCondition("stack[stack.length - 1]", 0)),
      "",
      "        case " + op.IF_ERROR + ":", // IF_ERROR t, f
      indent10(generateCondition(
        "stack[stack.length - 1] === peg$FAILED",
        0
      )),
      "",
      "        case " + op.IF_NOT_ERROR + ":", // IF_NOT_ERROR t, f
      indent10(
        generateCondition("stack[stack.length - 1] !== peg$FAILED",
          0
        )),
      "",
      "        case " + op.WHILE_NOT_ERROR + ":", // WHILE_NOT_ERROR b
      indent10(generateLoop("stack[stack.length - 1] !== peg$FAILED")),

case op.WRAP: // WRAP n
            parts.push(
              stack.push("[" + stack.pop(bc[ip + 1]).join(", ") + "]")
            );
            ip += 2;
            break;

          case op.TEXT: // TEXT
            parts.push(
              stack.push("input.substring(" + stack.pop() + ", peg$currPos)")
            );
            ip++;
            break;

          case op.IF: // IF t, f
            compileCondition(stack.top(), 0);
            break;

          case op.IF_ERROR: // IF_ERROR t, f
            compileCondition(stack.top() + " === peg$FAILED", 0);
            break;

          case op.IF_NOT_ERROR: // IF_NOT_ERROR t, f
            compileCondition(stack.top() + " !== peg$FAILED", 0);
            break;

          case op.WHILE_NOT_ERROR: // WHILE_NOT_ERROR b
            compileLoop(stack.top() + " !== peg$FAILED", 0);
            break;

          case op.MATCH_ANY: // MATCH_ANY a, f, ...

function buildSemanticPredicate(code, negative, context) {
    let functionIndex = addFunctionConst(Object.keys(context.env), code);

    return buildSequence(
      [op.UPDATE_SAVED_POS],
      buildCall(functionIndex, 0, context.env, context.sp),
      buildCondition(
        [op.IF],
        buildSequence(
          [op.POP],
          negative ? [op.PUSH_FAILED] : [op.PUSH_UNDEFINED]
        ),
        buildSequence(
          [op.POP],
          negative ? [op.PUSH_UNDEFINED] : [op.PUSH_FAILED]
        )
      )
    );
  }