initial commit

lua/import-cost.lua

@@ -0,0 +1,64 @@
+local M = {}
+
+local function is_ic_buf(bufnr)
+    local filetype = vim.api.nvim_buf_get_option(bufnr, 'filetype')
+
+    return vim.tbl_contains(M.config.filetypes, filetype)
+end
+
+local function au(events, cb)
+    vim.api.nvim_create_autocmd(events, {
+        callback = function(opts)
+            if is_ic_buf(opts.buf) then
+                cb(opts)
+            end
+        end,
+        group = M.aug_id,
+    })
+end
+
+M.config = {
+    filetypes = {
+        'javascript',
+        'javascriptreact',
+        'typescript',
+        'typescriptreact',
+    },
+    format = {
+        byte_format = '%.2f b',
+        kb_format = '%.2f kb',
+        virtual_text = '%s (gzipped: %s)',
+    },
+    highlight = 'Comment',
+}
+
+M.setup = function(user_config)
+    M.config = vim.tbl_deep_extend('force', M.config, user_config or {})
+
+    M.ns_id = vim.api.nvim_create_namespace 'ImportCost'
+
+    M.script_path = vim.fn.fnamemodify(debug.getinfo(1).source:sub(2), ':h:h')
+        .. '/import-cost/index.js'
+
+    vim.api.nvim_set_hl(
+        0,
+        'ImportCostVirtualText',
+        ---@diagnostic disable-next-line: param-type-mismatch
+        type(M.config.highlight) == 'string' and { link = M.config.highlight }
+            or M.config.highlight
+    )
+
+    M.aug_id = vim.api.nvim_create_augroup('ImportCost', {})
+
+    local extmark = require 'import-cost.extmark'
+
+    au({ 'BufEnter', 'BufWritePost' }, function(opts)
+        extmark.set_missing_extmarks(opts.buf)
+    end)
+
+    au('TextChanged', function(opts)
+        extmark.update_extmarks(opts.buf)
+    end)
+end
+
+return M

lua/import-cost/extmark.lua

@@ -0,0 +1,104 @@
+local M = {}
+
+local ic, job, util =
+    require 'import-cost', require 'import-cost.job', require 'import-cost.util'
+
+local visible_strings = {}
+
+local function update_visible_strings(bufnr, data, extmark_id)
+    if not visible_strings[bufnr] then
+        visible_strings[bufnr] = {}
+    end
+
+    visible_strings[bufnr][data.string] = data
+    visible_strings[bufnr][data.string].extmark_id = extmark_id
+end
+
+local function string_visible(bufnr, string)
+    return visible_strings[bufnr] and visible_strings[bufnr][string]
+end
+
+function M.set_missing_extmarks(bufnr)
+    local path = vim.api.nvim_buf_get_name(bufnr)
+    local filetype = vim.api.nvim_buf_get_option(bufnr, 'filetype')
+
+    local cmd = { 'node', ic.script_path, path, filetype }
+
+    local job_id = vim.fn.jobstart(cmd, {
+        on_stdout = function(_, stdout, _)
+            if not stdout or stdout[1] == '' then
+                return
+            end
+
+            local chunks = vim.split(stdout[1], '|', { trimempty = true })
+
+            for _, chunk in ipairs(chunks) do
+                local data = util.parse_data(chunk)
+
+                if util.is_ok(data) then
+                    local string = util.normalize_string(data.string)
+
+                    if not string_visible(bufnr, string) then
+                        data.string = string
+
+                        local extmark_id = job.set_extmark(bufnr, data)
+
+                        update_visible_strings(bufnr, data, extmark_id)
+                    end
+                end
+            end
+        end,
+    })
+
+    job.stop_prev_job(job_id, bufnr)
+    job.send_buf_contents(job_id, bufnr)
+end
+
+function M.clear_extmarks(bufnr)
+    if visible_strings[bufnr] then
+        visible_strings[bufnr] = nil
+    end
+
+    vim.api.nvim_buf_clear_namespace(bufnr, ic.ns_id, 0, -1)
+end
+
+function M.update_extmarks(bufnr)
+    local buffer_strings = M.move_existing_extmarks(bufnr)
+    M.delete_remaining_extmarks(bufnr, buffer_strings)
+    M.set_missing_extmarks(bufnr)
+end
+
+function M.move_existing_extmarks(bufnr)
+    local buffer_strings = {}
+
+    for nr, raw_string in ipairs(vim.api.nvim_buf_get_lines(bufnr, 0, -1, true)) do
+        if util.is_import_string(raw_string) then
+            local string = util.normalize_string(raw_string)
+            local data = visible_strings[bufnr][string]
+
+            buffer_strings[string] = true
+
+            if data and data.string == string then
+                if data.line ~= nr then
+                    data.line = nr
+
+                    job.set_extmark(bufnr, data, data.extmark_id)
+                end
+            end
+        end
+    end
+
+    return buffer_strings
+end
+
+function M.delete_remaining_extmarks(bufnr, buffer_strings)
+    for string, data in pairs(visible_strings[bufnr]) do
+        if not buffer_strings[string] then
+            vim.api.nvim_buf_del_extmark(bufnr, ic.ns_id, data.extmark_id)
+
+            visible_strings[bufnr][string] = nil
+        end
+    end
+end
+
+return M

lua/import-cost/import.lua

@@ -0,0 +1,3 @@
+local M = {}
+
+return M

lua/import-cost/job.lua

@@ -0,0 +1,48 @@
+local M = {}
+
+local ic = require 'import-cost'
+local format = ic.config.format
+
+local job_cache = {}
+
+local format_bytes = function(bytes)
+    if bytes < 1024 then
+        return string.format(format.byte_format, bytes)
+    end
+
+    return string.format(format.kb_format, 0.0009765625 * bytes)
+end
+
+function M.set_extmark(bufnr, data, extmark_id)
+    local line, size, gzip =
+        data.line - 1, format_bytes(data.size), format_bytes(data.gzip)
+
+    local virt_text = string.format(format.virtual_text, size, gzip)
+
+    return vim.api.nvim_buf_set_extmark(bufnr, ic.ns_id, line, -1, {
+        id = extmark_id,
+        virt_text = {
+            {
+                virt_text,
+                'ImportCostVirtualText',
+            },
+        },
+    })
+end
+
+function M.send_buf_contents(job_id, bufnr)
+    local contents = vim.api.nvim_buf_get_lines(bufnr, 0, -1, true)
+
+    vim.fn.chansend(job_id, contents)
+    vim.fn.chanclose(job_id, 'stdin')
+end
+
+function M.stop_prev_job(job_id, bufnr)
+    if job_cache[bufnr] then
+        vim.fn.jobstop(job_cache[bufnr])
+    end
+
+    job_cache[bufnr] = job_id
+end
+
+return M

lua/import-cost/util.lua

@@ -0,0 +1,39 @@
+local M = {}
+
+function M.is_import_string(string)
+    return string:sub(1, 6) == 'import' or string:sub(1, 5) == 'const'
+end
+
+function M.normalize_string(raw_string)
+    local string = raw_string
+
+    -- pad with semicolon
+    if string:sub(-1, -1) ~= ';' then
+        string = string .. ';'
+    end
+
+    -- stylua: ignore
+    string = string
+        :match('.-;') -- extract first statement
+        :gsub(' as %S+', '') -- remove aliases
+        :gsub("'", '"') -- swap single for double quotes
+        :gsub('%s+', '') -- remove whitespace
+
+    return string
+end
+
+function M.parse_data(chunk)
+    local ok, json = pcall(vim.fn.json_decode, chunk)
+
+    if not ok or not json then
+        return
+    end
+
+    return json.data
+end
+
+function M.is_ok(data)
+    return data and data.size
+end
+
+return M