feat: add inline subroutines

README.md

@@ -70,6 +70,7 @@ Have you got suggestions for improvement? [I am all ears](https://github.com/gaj
       * [Quantifier expression](#quantifier-expression)
     * [`test` subroutine](#test-subroutine)
   * [User-defined subroutines](#user-defined-subroutines)
+  * [Inline subroutines](#inline-subroutines)
   * [Built-in subroutine aliases](#built-in-subroutine-aliases)
 * [Expression reference](#expression-reference)
   * [The pipe operator (`|`)](#the-pipe-operator-)
@@ -457,6 +458,26 @@ For more examples of defining subroutines, refer to:
 * [Validate the results using a user-defined test function](#validate-the-results-using-a-user-defined-test-function).
 * [Source code](./src/subroutines) of the the built-in subroutines.
 
+## Inline subroutines
+
+Custom subroutines can be inlined into [pianola](https://github.com/gajus/pianola) instructions, e.g.
+
+```js
+x(
+  [
+    'foo',
+    (subject) => {
+      // `subject` is the return value of `foo` subroutine.
+
+      return 'bar';
+    },
+    'baz',
+  ],
+  'qux'
+);
+
+```
+
 ## Built-in subroutine aliases
 
 Surgeon exports an alias preset is used to reduce verbosity of the queries.

package.json

@@ -21,9 +21,9 @@
   "dependencies": {
     "cheerio": "^1.0.0-rc.3",
     "es6-error": "^4.1.1",
-    "pianola": "^2.1.1",
+    "pianola": "^2.2.0",
     "regex-parser": "^2.2.10",
-    "roarr": "^2.14.5"
+    "roarr": "^2.14.6"
   },
   "description": "Declarative DOM extraction expression evaluator.",
   "devDependencies": {
@@ -36,15 +36,15 @@
     "ava": "^2.4.0",
     "babel-plugin-istanbul": "^5.2.0",
     "babel-plugin-transform-export-default-name": "^2.0.4",
-    "coveralls": "^3.0.7",
+    "coveralls": "^3.0.8",
     "eslint": "^6.6.0",
     "eslint-config-canonical": "^18.1.0",
     "flow-bin": "^0.112.0",
-    "flow-copy-source": "^2.0.8",
-    "husky": "^3.0.9",
+    "flow-copy-source": "^2.0.9",
+    "husky": "^3.1.0",
     "lodash": "^4.17.15",
     "nyc": "^14.1.1",
-    "semantic-release": "^15.13.30",
+    "semantic-release": "^15.13.31",
     "sinon": "^7.5.0",
     "sprintf-js": "^1.1.2"
   },

test/surgeon/queries/single-match.js

@@ -134,3 +134,24 @@ test.skip('extracts a single value (expression string `.foo:has(+.bar)`)', (t):
 
   t.true(x(query, subject) === 'foo');
 });
+
+test('extracts a single value (using inline subroutine)', (t): void => {
+  const x = surgeon();
+
+  const subject = `
+    <div class="foo">FOO</div>
+    <div class="bar">BAR</div>
+  `;
+
+  const query: DenormalizedQueryType = [
+    'select .foo',
+    (input) => {
+      t.is(input.text(), 'FOO');
+
+      return input.next();
+    },
+    'read property textContent',
+  ];
+
+  t.is(x(query, subject), 'BAR');
+});