Add new CLI option debug-print-ast (#11514)

* Add new CLI option debug-print-ast

* Add tests

* Add changelog

* Remove text from ast

* Update tests/integration/__tests__/debug-print-ast.js

Co-authored-by: Georgii Dolzhykov <thorn.mailbox@gmail.com>

* Update tests

Co-authored-by: Georgii Dolzhykov <thorn.mailbox@gmail.com>

changelog_unreleased/cli/11514.md

@@ -0,0 +1,3 @@
+#### Add new CLI option `debug-print-ast` (#11514 by @sosukesuzuki)
+
+A new `--debug-print-ast` CLI flag for debugging.

src/cli/constant.js

@@ -135,6 +135,9 @@ const options = {
   "debug-print-comments": {
     type: "boolean",
   },
+  "debug-print-ast": {
+    type: "boolean",
+  },
   "debug-repeat": {
     // Repeat the formatting a few times and measure the average duration.
     type: "int",

src/cli/format.js

@@ -126,6 +126,13 @@ function format(context, input, opt) {
     };
   }
 
+  if (context.argv["debug-print-ast"]) {
+    const { ast } = prettier.__debug.parse(input, opt);
+    return {
+      formatted: JSON.stringify(ast),
+    };
+  }
+
   if (context.argv["debug-check"]) {
     const pp = prettier.format(input, opt);
     const pppp = prettier.format(pp, opt);

tests/integration/__tests__/__snapshots__/debug-print-ast.js.snap

@@ -0,0 +1,5 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`prints information for debugging AST --debug-print-ast (stdout) 1`] = `"{\\"type\\":\\"File\\",\\"start\\":0,\\"end\\":18,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":0},\\"end\\":{\\"line\\":1,\\"column\\":18}},\\"range\\":[0,18],\\"errors\\":[],\\"program\\":{\\"type\\":\\"Program\\",\\"start\\":0,\\"end\\":18,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":0},\\"end\\":{\\"line\\":1,\\"column\\":18}},\\"range\\":[0,18],\\"sourceType\\":\\"module\\",\\"interpreter\\":null,\\"body\\":[{\\"type\\":\\"VariableDeclaration\\",\\"start\\":0,\\"end\\":18,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":0},\\"end\\":{\\"line\\":1,\\"column\\":18}},\\"range\\":[0,18],\\"declarations\\":[{\\"type\\":\\"VariableDeclarator\\",\\"start\\":6,\\"end\\":17,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":6},\\"end\\":{\\"line\\":1,\\"column\\":17}},\\"range\\":[6,17],\\"id\\":{\\"type\\":\\"Identifier\\",\\"start\\":6,\\"end\\":9,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":6},\\"end\\":{\\"line\\":1,\\"column\\":9},\\"identifierName\\":\\"foo\\"},\\"range\\":[6,9],\\"name\\":\\"foo\\"},\\"init\\":{\\"type\\":\\"StringLiteral\\",\\"start\\":12,\\"end\\":17,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":12},\\"end\\":{\\"line\\":1,\\"column\\":17}},\\"range\\":[12,17],\\"extra\\":{\\"rawValue\\":\\"foo\\",\\"raw\\":\\"'foo'\\"},\\"value\\":\\"foo\\"}}],\\"kind\\":\\"const\\"}],\\"directives\\":[]},\\"comments\\":[],\\"tokens\\":[{\\"type\\":{\\"label\\":\\"const\\",\\"keyword\\":\\"const\\",\\"beforeExpr\\":false,\\"startsExpr\\":false,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":false,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"value\\":\\"const\\",\\"start\\":0,\\"end\\":5,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":0},\\"end\\":{\\"line\\":1,\\"column\\":5}}},{\\"type\\":{\\"label\\":\\"name\\",\\"beforeExpr\\":false,\\"startsExpr\\":true,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":false,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"value\\":\\"foo\\",\\"start\\":6,\\"end\\":9,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":6},\\"end\\":{\\"line\\":1,\\"column\\":9}}},{\\"type\\":{\\"label\\":\\"=\\",\\"beforeExpr\\":true,\\"startsExpr\\":false,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":true,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"value\\":\\"=\\",\\"start\\":10,\\"end\\":11,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":10},\\"end\\":{\\"line\\":1,\\"column\\":11}}},{\\"type\\":{\\"label\\":\\"string\\",\\"beforeExpr\\":false,\\"startsExpr\\":true,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":false,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"value\\":\\"foo\\",\\"start\\":12,\\"end\\":17,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":12},\\"end\\":{\\"line\\":1,\\"column\\":17}}},{\\"type\\":{\\"label\\":\\";\\",\\"beforeExpr\\":true,\\"startsExpr\\":false,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":false,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"start\\":17,\\"end\\":18,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":17},\\"end\\":{\\"line\\":1,\\"column\\":18}}},{\\"type\\":{\\"label\\":\\"eof\\",\\"beforeExpr\\":false,\\"startsExpr\\":false,\\"rightAssociative\\":false,\\"isLoop\\":false,\\"isAssign\\":false,\\"prefix\\":false,\\"postfix\\":false,\\"binop\\":null,\\"updateContext\\":null},\\"start\\":18,\\"end\\":18,\\"loc\\":{\\"start\\":{\\"line\\":1,\\"column\\":18},\\"end\\":{\\"line\\":1,\\"column\\":18}}}]}"`;
+
+exports[`prints information for debugging AST --debug-print-ast (write) 1`] = `Array []`;

tests/integration/__tests__/debug-print-ast.js

@@ -0,0 +1,12 @@
+"use strict";
+
+const runPrettier = require("../runPrettier.js");
+
+describe("prints information for debugging AST --debug-print-ast", () => {
+  runPrettier("cli/with-shebang", ["--debug-print-ast", "--parser", "babel"], {
+    input: "const foo = 'foo';",
+  }).test({
+    stderr: "",
+    status: 0,
+  });
+});