Add debug logging (#83)

Author: Turbo87

bin/cli.js

@@ -1,12 +1,21 @@
 #!/usr/bin/env node
 'use strict';
 
-const { gatherTelemetryForUrl, analyzeEmberObject } = require('ember-codemods-telemetry-helpers');
+const debug = require('debug')('ember-no-implicit-this-codemod');
+const {
+  gatherTelemetryForUrl,
+  analyzeEmberObject,
+  getTelemetry,
+} = require('ember-codemods-telemetry-helpers');
 const appLocation = process.argv[2];
 const args = process.argv.slice(3);
 
 (async () => {
+  debug('Gathering telemetry data from %s ...', appLocation);
   await gatherTelemetryForUrl(appLocation, analyzeEmberObject);
 
+  let telemetry = getTelemetry();
+  debug('Gathered telemetry on %d modules', Object.keys(telemetry).length);
+
   require('codemod-cli').runTransform(__dirname, 'no-implicit-this', args, 'hbs');
 })();

package.json

@@ -32,6 +32,7 @@
   ],
   "dependencies": {
     "codemod-cli": "^2.1.0",
+    "debug": "^4.1.1",
     "ember-codemods-telemetry-helpers": "^1.1.0",
     "ember-template-recast": "^3.3.0"
   },

transforms/no-implicit-this/helpers/plugin.js

@@ -1,3 +1,4 @@
+const debug = require('debug')('ember-no-implicit-this-codemod:plugin');
 const recast = require('ember-template-recast');
 
 // everything is copy-pasteable to astexplorer.net.
@@ -47,33 +48,66 @@ function transform(root, options = {}) {
 
   function handlePathExpression(node) {
     // skip this.foo
-    if (node.this) return;
+    if (node.this) {
+      debug(`Skipping \`%s\` because it is already prefixed with \`this.\``, node.original);
+      return;
+    }
 
     // skip @foo
-    if (node.data) return;
+    if (node.data) {
+      debug(`Skipping \`%s\` because it is already prefixed with \`@\``, node.original);
+      return;
+    }
 
     // skip {#foo as |bar|}}{{bar}}{{/foo}}
     // skip <Foo as |bar|>{{bar}}</Foo>
     let firstPart = node.parts[0];
-    if (scopedParams.includes(firstPart)) return;
+    if (scopedParams.includes(firstPart)) {
+      debug(`Skipping \`%s\` because it is a scoped variable`, node.original);
+      return;
+    }
 
     // skip `hasBlock` keyword
-    if (node.original === 'hasBlock') return;
+    if (node.original === 'hasBlock') {
+      debug(`Skipping \`%s\` because it is a keyword`, node.original);
+      return;
+    }
 
     // add `this.` prefix
+    debug(`Transforming \`%s\` to \`this.%s\``, node.original, node.original);
     Object.assign(node, b.path(`this.${node.original}`));
   }
 
   function isHelper(name) {
-    return (
-      KNOWN_HELPERS.includes(name) ||
-      customHelpers.includes(name) ||
-      Boolean(helpers.find(path => path.endsWith(name)))
-    );
+    if (KNOWN_HELPERS.includes(name)) {
+      debug(`Skipping \`%s\` because it is a known helper`, name);
+      return true;
+    }
+
+    if (customHelpers.includes(name)) {
+      debug(`Skipping \`%s\` because it is a custom configured helper`, name);
+      return true;
+    }
+
+    let helper = helpers.find(path => path.endsWith(name));
+    if (helper) {
+      let message = `Skipping \`%s\` because it appears to be a helper from the telemetry data: %s`;
+      debug(message, name, helper);
+      return true;
+    }
+
+    return false;
   }
 
   function isComponent(name) {
-    return Boolean(components.find(path => path.endsWith(name)));
+    let component = components.find(path => path.endsWith(name));
+    if (component) {
+      let message = `Skipping \`%s\` because it appears to be a component from the telemetry data: %s`;
+      debug(message, name, component);
+      return true;
+    }
+
+    return false;
   }
 
   let inAttrNode = false;
@@ -113,7 +147,11 @@ function transform(root, options = {}) {
 
         // skip ember-holy-futuristic-template-namespacing-batman component/helper invocations
         // (see https://github.com/rwjblue/ember-holy-futuristic-template-namespacing-batman)
-        if (path.original.includes('$') || path.original.includes('::')) return;
+        if (path.original.includes('$') || path.original.includes('::')) {
+          let message = `Skipping \`%s\` because it looks like a helper/component invocation from ember-holy-futuristic-template-namespacing-batman`;
+          debug(message, path.original);
+          return;
+        }
 
         // skip helpers
         if (isHelper(path.original)) return;

transforms/no-implicit-this/index.js

@@ -1,6 +1,7 @@
 const path = require('path');
 const fs = require('fs');
 
+const debug = require('debug')('ember-no-implicit-this-codemod:transform');
 const recast = require('ember-template-recast');
 const { getTelemetry } = require('ember-codemods-telemetry-helpers');
 const transform = require('./helpers/plugin');
@@ -45,11 +46,18 @@ module.exports = function transformer(file /*, api */) {
   let options = Object.assign({}, DEFAULT_OPTIONS, getOptions());
 
   if (!['.hbs'].includes(extension.toLowerCase())) {
+    debug('Skipping %s because it does not match the .hbs file extension', file.path);
+
     // do nothing on non-hbs files
     return;
   }
 
+  debug('Parsing %s ...', file.path);
   let root = recast.parse(file.source);
+
+  debug('Transforming %s ...', file.path);
   transform(root, options);
+
+  debug('Generating new content for %s ...', file.path);
   return recast.print(root);
 };