Debugging with dap-mode

• Per-language configuration: https://emacs-lsp.github.io/dap-mode/page/configuration/
• Make sure lsp-mode is active otherwise `workspaceFolder` won’t be available

(use-package dap-mode)

In your TypeScript / JavaScript configuration:

(require 'dap-node)
(dap-node-setup) ;; Automatically installs Node debug adapter if needed

• dap-debug: Select a template to execute
• dap-debug-last: Run the most recent template
• dap-debug-recent: Select a recent template to run
• dap-disconnect: Disconnect from the debugging session (output buffer retained)
• dap-delete-session: Delete the current session (output buffer will be deleted)
• dap-delete-all-sessions: Clean up all debugging sessions

• dap-debug-edit-template: Present a debug template for editing

(dap-register-debug-template
  "Debug Server"
  (list :type "node"
        :request "launch"
        :program "${workspaceFolder}/src/server/index.ts"
        :outFiles ["${workspaceFolder}/public/src/server/**/*.js"]
        :name "Debug Server"))

• dap-breakpoint-toggle: Toggle a breakpoint on the current line
• dap-breakpoint-delete-all: Delete all breakpoints in the workspace
• dap-breakpoint-condition: Set condition for breakpoint
• dap-breakpoint-hit-condition: Set hit condition, number of hits before breakpoint stops
• dap-breakpoint-log-message: Set log message for breakpoint (interpolate expressions with {})
• dap-ui-breakpoints: Show breakpoints panel

• dap-hydra: Quick panel for debugging commands
• Keep in mind, the Hydra will capture keys unexpectedly (M-x, etc)
• Automatically show Hydra when debugger stops:

:hook (dap-stopped . (lambda (arg) (call-interactively #'dap-hydra))))

• dap-ui-expressions-add: Add a watch expression
• dap-ui-expressions-remove: Remove a watch expression

• dap-ui-repl: Start a debugging REPL for your language (if supported)
• M-n / M-p: Go forward/back in REPL command history

• dap-tooltip-mode: Turns it on
• dap-tooltip-at-point: Show the value at the current point
• Not working?

If you’re working in a project where other people use VS Code, this is valuable!

• Use pre-created config

Here’s how to customize the UI to show only what you care about

• dap-auto-configure-features
• OR
• lsp-enable-dap-auto-configure and dap-ui-mode
• dap-auto-show-output: If t (default), show output buffer when running
• dap-go-to-output-buffer

(use-package dap-mode
  :custom
  (dap-auto-configure-features '(sessions locals tooltip))
  :config
  (setq lsp-enable-dap-auto-configure nil)
  ;; (dap-ui-mode 1)
  (general-define-key
    :keymaps 'lsp-mode-map
    :prefix lsp-keymap-prefix
    "d" '(dap-hydra t :wk "debugger")))