From a80aeb2f7f53cee94744fad7ee6b287c1720abec Mon Sep 17 00:00:00 2001
From: "Dylan R. E. Moonfire" <d.moonfire@mfgames.com>
Date: Thu, 27 Aug 2020 20:54:28 -0500
Subject: [PATCH] feat(extract): added additional options to extract

- `--no-list` to not write the output as a list of objects
- `--yaml` to write the output as YAML
- `--content` to extract the content of a property of the given name
- Updated read me to include usage of extract
---
 README.md            | 14 ++++++++
 package-lock.json    |  9 +++++
 package.json         |  1 +
 src/tools/extract.ts | 79 +++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 94 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 25a8899..c8a40c1 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,20 @@ Options:
 * `-t`, `--total`: Add a total line to the bottom that combines.
 * `-s`, `--separator`: Comma-separates the numbers in the total.
 
+### extract
+
+> Extract the metadata (front matter) from one or more files.
+
+```sh
+markdowny extract *.markdown [options]
+```
+
+Options:
+
+* `--no-list`: Don't write out the extract data as a list/sequence of items (default).
+* `-y`, `--yaml`: Extract the data as YAML instead of JSON (default).
+* `--content PROPERTY`: Extract the content as a property of the given name instead of just removing it. Defaults to not extracting the content.
+
 ### sections
 
 > Displays each file as a heading 1 section with the title and contents provided.
diff --git a/package-lock.json b/package-lock.json
index a799d84..fe6de47 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1699,6 +1699,15 @@
       "integrity": "sha512-wWKOClTTiizcZhXnPY4wikVAwmdYHp8q6DmC+EJUzAMsycb7HB32Kh9RN4+0gExjmPmZSAQjgURXIGATPegAvA==",
       "dev": true
     },
+    "@types/yaml": {
+      "version": "1.9.7",
+      "resolved": "https://registry.npmjs.org/@types/yaml/-/yaml-1.9.7.tgz",
+      "integrity": "sha512-8WMXRDD1D+wCohjfslHDgICd2JtMATZU8CkhH8LVJqcJs6dyYj5TGptzP8wApbmEullGBSsCEzzap73DQ1HJaA==",
+      "dev": true,
+      "requires": {
+        "yaml": "*"
+      }
+    },
     "@types/yargs": {
       "version": "11.1.6",
       "resolved": "https://registry.npmjs.org/@types/yargs/-/yargs-11.1.6.tgz",
diff --git a/package.json b/package.json
index 0928acf..d937428 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "@semantic-release/npm": "^5.0.1",
     "@types/lodash": "^4.14.116",
     "@types/read-pkg-up": "^3.0.1",
+    "@types/yaml": "^1.9.7",
     "@types/yargs": "^11.1.1",
     "barrelsby": "^1.0.2",
     "commitizen": "^2.10.1",
diff --git a/src/tools/extract.ts b/src/tools/extract.ts
index 473e473..9aa4e78 100644
--- a/src/tools/extract.ts
+++ b/src/tools/extract.ts
@@ -1,6 +1,8 @@
 import * as _ from "lodash";
-import * as yargs from "yargs";
+import * as fs from "fs";
 import * as scanner from "../scanner";
+import * as yaml from "js-yaml";
+import * as yargs from "yargs";
 
 export var command = "extract";
 export var describe = "Extracts a YAML from a list of files";
@@ -10,20 +12,79 @@ export function builder(yargs: yargs.Arguments)
     return yargs
         .help("help")
 
-        .alias("o", "output")
-        .default("output", "-")
+        .option(
+            "list",
+            {
+                type: "boolean",
+                default: true,
+                describe: "Extract the data as a list of files, otherwise as a single file",
+            }
+        )
+        .option(
+            "output",
+            {
+                alias: "o",
+                default: "-",
+                describe: "Write output to a file or `-` for standard out",
+            }
+        )
+        .option(
+            "yaml",
+            {
+                alias: "y",
+                type: "boolean",
+                default: false,
+                describe: "Extract the output as YAML instead of JSON",
+            }
+        )
+        .option(
+            "content",
+            {
+                type: "string",
+                describe: "Include the content as a property in the extracted data",
+            }
+        )
 
         .demand(1);
 }
 
 export function handler(argv: any)
 {
+    // Parse through the files and retrieve the metadata.
     var files = argv._.splice(1);
-    var data = scanner.scanFiles(argv, files);
-    render(argv, data);
-}
+    var data: any = scanner.scanFiles(argv, files);
 
-export function render(argv, data)
-{
-    console.log(JSON.stringify(data));
+    // Figure out how to handle the content property.
+    if (!argv.content)
+    {
+        // Remove the content from the parsed file.
+        data.forEach(x => delete x.__content);
+    } else if (argv.content !== "__content")
+    {
+        // Rename the content property.
+        data.forEach(x => {
+            x[argv.content] = x.__content;
+            delete x.__content;
+        })
+    }
+
+    // Determine if we are displaying a list of items. If we want a list, then
+    // we wrap the data in another list (list of a list) so it writes out only
+    // one item. Otherwise, we write out each one.
+    const items = argv.list
+        ? [data]
+        : data;
+
+    // Figure the output of the results (JSON or YAML).
+    const output = argv.yaml
+        ? items.map((x: any) => yaml.safeDump(x)).join("\n")
+        : items.map((x: any) => JSON.stringify(x)).join("\n");
+
+    // Figure out where to write.
+    if (argv.output === "-")
+    {
+        console.log(output);
+    } else {
+        fs.writeFileSync(argv.output, Buffer.from(output, "utf-8"));
+    }
 }