doc.md

cd /tmp
# wait treesitter#main setup
nvim --clean -u slow-ts.lua
# exit nvim
# edit test.vue file
nvim --clean -u slow-ts.lua test.vue

steps

1. use Ctrl+d to move cursor to line 26, do not use :26 to move cursor, the result is different (strange :().
2. start insert comment above line 26 with /***, you can feel the slowness.

slow-ts.lua

vim.g.mapleader = " "
vim.g.maplocalleader = ","
vim.opt.showcmd = true
vim.opt.showcmdloc = "last"
vim.opt.breakindent = true
vim.opt.number = true

for name, url in pairs({
	-- ADD PLUGINS _NECESSARY_ TO REPRODUCE THE ISSUE, e.g:
	-- some_plugin = 'https://github.com/author/plugin.nvim'
	treesitter = "https://github.com/nvim-treesitter/nvim-treesitter",
}) do
	local install_path = vim.fn.fnamemodify("slow_ts/" .. name, ":p")
	if vim.fn.isdirectory(install_path) == 0 then
		if name == "treesitter" then
			vim.fn.system({ "git", "clone", "--branch", "main", "--depth=1", url, install_path })
		else
			vim.fn.system({ "git", "clone", "--depth=1", url, install_path })
		end
	end
	vim.opt.runtimepath:append(install_path)
end

-- ===============

require("nvim-treesitter").setup({
	ensure_install = { "vue", "javascript", "typescript", "comment", "jsdoc" },
	auto_install = false,
	install_dir = vim.fn.fnamemodify("slow_ts/.site", ":p"),
})

local ftau = vim.api.nvim_create_augroup("option_ft", { clear = true })
vim.api.nvim_create_autocmd("FileType", {
	group = ftau,
	pattern = { "*" },
	callback = function(args)
		local buf = args.buf
		-- start highlighter.
		if not pcall(vim.treesitter.start, buf) then
			print("ERROR! highlight not started")
			return
		end
	end,
})

vim.cmd("colorscheme default")

test.vue

<template>
  <div>hello</div>
</template>

<script>
export default {
  name: "Test",

  components: {},

  props: {
    close: {
      type: Function,
    },
    visible: {
      type: Boolean,
      default: false,
    },
    payload: {
      type: Object,
    },
  },

  data() {
    return {
      shoobPicker: false,
      showMore: false,
      editData: {},
      prosList: [],
      prosEntst: [],
      groupIndexMap: {},
      itemIndexMap: {},
      isFeinsvntList: true,
      isLoading: false,
      ids: [],
      treeStpGroups: [],
      poonList: [],
      poiisTotal: 0,
      addedJos: [],
      removJs: [],
    };
  },
  computed: {
    title() {
      if (this.isAdd) {
        return "赛单反龙矿将发";
      }
      return "赛看扽开奖发";
    },
    isAdd() {
      return !this.editData.id;
    },
    isDefault() {
      return !!this.editData.defaultConfig;
    },
    addedJobIds() {
      return map(this.addedJos, (j) => j.positionId);
    },
    removedJobIds() {
      return map(this.removedJobs, (j) => j.positionId);
    },
    moreJobsCount() {
      if (!this.positionsTotal && !this.addedJobIds.length) {
        return 0;
      }
      if (this.positionsTotal <= 10) {
        return 0;
      }

      return (
        this.positionsTotal +
        this.addedJobIds.length -
        this.removedJobIds.length -
        this.jobsToDisplay.length
      );
    },
    jobsToDisplay() {
      const added = unionBy(this.positionList, this.addedJobs, "positionId");
      return filter(
        added,
        (job) => !includes(this.removedJobIds, job.positionId),
      );
    },
  },

  methods: {
    async fesiinyd(id) {
      const data = await fetchtions(id);
      this.positionList = data.data || [];
      this.positionsTotal = data.total;
    },
    onbsChanged(added, removed) {
      this.addedJbs = added;
      this.removedJbs = removed;
      this.showJobPer = false;
    },
    onSave() {
      const payload = {
        ...this.editData,
      };
      payload.items = reduce(
        this.treeStepsGroups,
        (acc, group) => {
          group.children.forEach((item) => {
            acc.push({
              id: item.id,
              name: item.name || item.event_name,
              reward: item.number,
              processPhaseId: group.phase_id,
              processEventCode: item.event_code,
              templateId: item.template_id,
            });
          });
          return acc;
        },
        [],
      );
      this.$emit("save", payload, {
        added: this.addedJobIds.slice(),
        removed: this.removedJobIds.slice(),
      });
    },
    onClose() {
      this.showJobPicker = false;
      if (this.close) {
        this.close();
      }
      this.reset();
    },
    reset() {
      this.showJobPicker = false;
      this.showMore = false;
      this.editData = {};
      this.processList = [];
      this.processEventList = [];
      this.groupIndexMap = {};
      this.itemIndexMap = {};
      this.isFetchingProcessEventList = true;
      this.isLoading = false;
      this.ids = [];
      this.treeStepsGroups = [];
      this.positionList = [];
      this.positionsTotal = 0;
      this.addedJobs = [];
      this.removedJobs = [];
    },
    async init() {
      if (!this.visible) {
        this.reset();
        return;
      }
      this.isLoading = true;
      if (this.payload.id) {
        // is edit.
        this.editData = await fetchail(this.payload.id);
        this.fetchSeitionsById(this.payload.id);
      } else {
        // is add.
        this.editData = {
          ...this.payload,
          phaseItems: [],
        };
      }
      this.ids = getSeedEventIeItems(
        this.editta.phaseItems || [],
      );
      this.fetchPrist();
      await this.fetchPenist();
      this.treeStepsGroups = transSesoups(
        this.editData.phaseItems,
        this.groupIndexMap,
        this.itemIndexMap,
      );
      this.isLoading = false;
    },
    /**
     * 赛框架反馈搜到饭
     */
    async fetchProcessList() {
      // 扫单反搜到肌肤搜到了发
      if (!this.isAdd && this.procist.length) {
        return;
      }
      const list = await fetcnfV2ocessList();
      this.processList = list;
    },
    /**
     * 空蓝扽看三扽囧两肯将
     */
    async fetchPentList() {
      if (!this.editData.atPossId) {
        return;
      }
      const atsProcessId = this.editData.atsProcessId;
      this.isFetngProcntList = true;
      try {
        const list = await fetchntList({
          process_id: this.editData.atsProcessId,
        });
        if (atsProcessId !== this.editData.atsProcessId) {
          return;
        }
       const value = transormProcpseCheckboxGroups(list);
        this.processEventList = value.groups;
        this.groupIndexMap = value.groupIndexMap;
        this.itemIndexMap = value.itemIndexMap;
      } catch (err) {
        this.$message.error(err.message);
      } finally {
        this.isFetchingProcessEventList = false;
      }
    },
    async onAtsProcessChange() {
      this.treeStepsGroups = [];
      this.ids = [];
      this.positionList = [];
      this.positionsTotal = 0;
      this.addedJobs = [];
      this.removedJobs = [];

      await this.fetchProcessEventList();
    },
    onTodified(newTplIds, oldTplIds) {
      const [removed, added] = diffTwoArray(oldTplIds || [], newTplIds || []);
      if (removed.length) {
        removed.forEach((item) => {
          rastmroTeSesops(this.treeStepsGroups, item);
        });
      }
      if (added.length) {
        added.forEach((item) => {
          addPheeToTeSesGroups(
            this.treeepsGroups,
            item,
            this.processEventList,
          );
        });
      }
    },
    onRemoveRuleItem(group, index, item) {
      const id = item.value;
      removPmepops(this.treeStepsGroups, id);
      this.ids = filter(this.ids, (id_) => id_ != id);
    },
    onRuleIluehne(value, group, index, item) {
      item.number = value;
    },
  },
};
};
</script>

<style lang="scss">
.Test {
}
</style>

Better way to get to line 26: 26ggzt. C-d is a bit annoying since dependent on screen size.

init.lua can be shorted and still reproduces:

local install_path = vim.fn.fnamemodify("slow_ts/treesitter", ":p")
local url = "https://github.com/nvim-treesitter/nvim-treesitter"
vim.fn.system({ "git", "clone", "--branch", "main", "--depth=1", url, install_path })
if vim.fn.isdirectory(install_path) == 0 then
  vim.opt.runtimepath:append(install_path)
end

require("nvim-treesitter").setup({
  ensure_install = { "vue", "javascript", "typescript", "comment", "jsdoc" },
  auto_install = false,
  install_dir = vim.fn.fnamemodify("slow_ts/.site", ":p"),
})

-- ^ not core to repro; only for installing parsers --

vim.api.nvim_create_autocmd("FileType", {
  pattern = { "*" },
  callback = function() vim.treesitter.start() end,
})