Repository: ViacomInc/data-point (js)

Issue:
codemod for PathReducer change of $. to $
**Problem description**:

#52  deprecates `$.` in favor of `$` which adds a breaking change

**Suggested solution**:

Create a codemod under data-point-codemds that will refactor any instance of `$.` to `$`

`'$.'` to `'$'` 
`'$. |..'` to `'$ |..'` 

applies to strings and string literals


Pull request:
feat(data-point-codemods): Add codemod for changing PathReducer from $. to $
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BREAKING CHANGES:

If your PR includes a breaking change, please submit it with a codemod under
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Breaking changes without a codemod will not be accepted unless a codemod is not
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<!-- What changes are being made? (What feature/bug is being fixed here?) -->
**What**: Adds a codemod to change `$.` to `$` if found in a string or template literal

<!-- Why are these changes necessary? -->
**Why**: Closes #179

<!-- How were these changes implemented? -->
**How**: http://http://astexplorer.net

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**Checklist**:
<!-- add "N/A" to the end of each line that's irrelevant to your changes -->
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- [ ] Has Breaking changes
- [X] Documentation
- [X] Tests
- [X] Ready to be merged <!-- In your opinion, is this ready to be merged as soon as it's reviewed? -->
- [ ] Added username to **all-contributors** list

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Patch:
diff --git a/packages/data-point-codemods/README.md b/packages/data-point-codemods/README.md
index c609be6..2df8236 100644
--- a/packages/data-point-codemods/README.md
+++ b/packages/data-point-codemods/README.md
@@ -38,6 +38,7 @@ data-point-codemods --help
 
 - ([codemod](transforms/reducer-args-acc-to-val-acc.js)) Refactor ReducerFunctions for value as first parameter eg. `(acc)` &rarr; `(input, acc)`. For more info please look at the [input](transforms/__testfixtures__/reducer-args-acc-to-val-acc.input.js)/[output](transforms/__testfixtures__/reducer-args-acc-to-val-acc.output.js) tests.
 
+- ([codemod](transforms/change-path-reducer-accessing-root-path.js)) Refactor PathReducers that access the root with `$.` to use `$`. For more info please look at the [input](transforms/__testfixtures__/change-path-reducer-accessing-root-path.input.js)/[output](transforms/__testfixtures__/change-path-reducer-accessing-root-path.output.js) tests.
 
 ## WARNING
 
diff --git a/packages/data-point-codemods/transforms/change-path-reducer-accessing-root-path.js b/packages/data-point-codemods/transforms/change-path-reducer-accessing-root-path.js
new file mode 100644
index 0000000..d21c809
--- /dev/null
+++ b/packages/data-point-codemods/transforms/change-path-reducer-accessing-root-path.js
@@ -0,0 +1,62 @@
+module.exports = (file, api) => {
+  const j = api.jscodeshift
+  const rootPathWithDotRegex = /\$\.(\s|$)/g
+
+  const root = j(file.source)
+
+  function detectQuoteStyle (j, root) {
+    let detectedQuoting = 'single'
+
+    root
+      .find(j.Literal, {
+        value: v => typeof v === 'string',
+        raw: v => typeof v === 'string'
+      })
+      .forEach(p => {
+        // The raw value is from the original babel source
+        if (p.value.raw[0] === "'") {
+          detectedQuoting = 'single'
+        }
+
+        if (p.value.raw[0] === '"') {
+          detectedQuoting = 'double'
+        }
+      })
+
+    return detectedQuoting
+  }
+
+  // transforms a string from '$. | $. | $.' -> '$ | $ | $'
+  function transformLiteral (node) {
+    const originalValue = node.value.value
+    if (rootPathWithDotRegex.test(originalValue)) {
+      node.value.value = node.value.value.replace(rootPathWithDotRegex, '$$$1')
+    }
+  }
+
+  // transforms a template literal from `$. | $. | $.` -> `$ | $ | $`
+  function transformTemplateElement (node) {
+    const originalValue = node.value.value.raw
+    if (rootPathWithDotRegex.test(originalValue)) {
+      node.value.value.raw = node.value.value.raw.replace(
+        rootPathWithDotRegex,
+        '$$$1'
+      )
+    }
+  }
+
+  function refactorReducerMatches (nodeType, transform) {
+    root.find(nodeType).forEach(transform)
+  }
+
+  refactorReducerMatches(j.Literal, transformLiteral)
+  refactorReducerMatches(j.TemplateElement, transformTemplateElement)
+
+  // As Recast is not preserving original quoting, we try to detect it,
+  // and default to something sane.
+  // See https://github.com/benjamn/recast/issues/171
+  // and https://github.com/facebook/jscodeshift/issues/143
+  // credit to @skovhus: https://github.com/avajs/ava-codemods/pull/28
+  const quote = detectQuoteStyle(j, root)
+  return root.toSource({ quote })
+}


Test patch:
diff --git a/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.input.js b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.input.js
new file mode 100644
index 0000000..125d409
--- /dev/null
+++ b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.input.js
@@ -0,0 +1,22 @@
+/* eslint-disable */
+/* eslint-disable prettier */
+
+// prettier-ignore
+const entities = {
+  'transform:a': `$.`,
+  'transform:b': `$. | foo | $.`,
+  'transform:c': `foo | bar | baz`,
+  'transform:d': "$.",
+  'transform:e': "$. | foo",
+  'transform:f': "$. | $. | $.",
+  'transform:g': "foo | bar | baz",
+  nested: {
+    object: {
+      a: "$. | $."
+    },
+    array: ["$.", "'$.", "$."]
+  }
+}
+
+// prettier-ignore
+dataPoint.transform("foo | $. | baz | $.")
diff --git a/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.output.js b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.output.js
new file mode 100644
index 0000000..12624ba
--- /dev/null
+++ b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-double-quote.output.js
@@ -0,0 +1,22 @@
+/* eslint-disable */
+/* eslint-disable prettier */
+
+// prettier-ignore
+const entities = {
+  'transform:a': `$`,
+  'transform:b': `$ | foo | $`,
+  'transform:c': `foo | bar | baz`,
+  'transform:d': "$",
+  'transform:e': "$ | foo",
+  'transform:f': "$ | $ | $",
+  'transform:g': "foo | bar | baz",
+  nested: {
+    object: {
+      a: "$ | $"
+    },
+    array: ["$", "'$", "$"]
+  }
+}
+
+// prettier-ignore
+dataPoint.transform("foo | $ | baz | $")
diff --git a/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.input.js b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.input.js
new file mode 100644
index 0000000..bbe8274
--- /dev/null
+++ b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.input.js
@@ -0,0 +1,21 @@
+/* eslint-disable */
+/* eslint-disable prettier */
+
+// prettier-ignore
+const entities = {
+  'transform:a': `$.`,
+  'transform:b': `$. | foo | $.`,
+  'transform:c': `foo | bar | baz`,
+  'transform:d': '$.',
+  'transform:e': '$. | foo',
+  'transform:f': '$. | $. | $.',
+  'transform:g': 'foo | bar | baz',
+  nested: {
+    object: {
+      a: '$. | $.'
+    },
+    array: ['$.', '$.', '$.']
+  }
+}
+
+dataPoint.transform('foo | $. | baz | $.')
diff --git a/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.output.js b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.output.js
new file mode 100644
index 0000000..d56ce5a
--- /dev/null
+++ b/packages/data-point-codemods/transforms/__testfixtures__/change-path-reducer-accessing-root-path-single-quote.output.js
@@ -0,0 +1,21 @@
+/* eslint-disable */
+/* eslint-disable prettier */
+
+// prettier-ignore
+const entities = {
+  'transform:a': `$`,
+  'transform:b': `$ | foo | $`,
+  'transform:c': `foo | bar | baz`,
+  'transform:d': '$',
+  'transform:e': '$ | foo',
+  'transform:f': '$ | $ | $',
+  'transform:g': 'foo | bar | baz',
+  nested: {
+    object: {
+      a: '$ | $'
+    },
+    array: ['$', '$', '$']
+  }
+}
+
+dataPoint.transform('foo | $ | baz | $')
diff --git a/packages/data-point-codemods/transforms/__tests__/change-path-reducer-accessing-root-path.test.js b/packages/data-point-codemods/transforms/__tests__/change-path-reducer-accessing-root-path.test.js
new file mode 100644
index 0000000..551f84b
--- /dev/null
+++ b/packages/data-point-codemods/transforms/__tests__/change-path-reducer-accessing-root-path.test.js
@@ -0,0 +1,21 @@
+/* eslint-env jest */
+
+'use strict'
+
+const { defineTest } = require('jscodeshift/dist/testUtils')
+
+// single quote
+defineTest(
+  __dirname,
+  'change-path-reducer-accessing-root-path',
+  null,
+  'change-path-reducer-accessing-root-path-single-quote'
+)
+
+// double quote
+defineTest(
+  __dirname,
+  'change-path-reducer-accessing-root-path',
+  null,
+  'change-path-reducer-accessing-root-path-double-quote'
+)