feat: add threshold for bundle size increase notifications

README.md

@@ -103,14 +103,14 @@ This action requires the `write` permission for the [`permissions.pull-requests`
 
 ## Options
 
-| name                    | description                                                                                                         | required | type   |
-| ----------------------- | ------------------------------------------------------------------------------------------------------------------- | -------- | ------ |
-| current-stats-json-path | The path to the current stats.json file                                                                             | true     | string |
-| base-stats-json-path    | The path to the base stats.json file                                                                                | true     | string |
-| github-token            | The Github token                                                                                                    | true     | string |
-| title                   | An optional addition to the title, which also helps key comments, useful if running more than 1 copy of this action | false    | string |
-
-| describe-assets         | Option for asset description output. One of "all" (default), "changed-only", or "none". | false    | string |
+| name                             | description                                                                                                         | required | type   |
+| -------------------------------- | ------------------------------------------------------------------------------------------------------------------- | -------- | ------ |
+| current-stats-json-path          | The path to the current stats.json file                                                                             | true     | string |
+| base-stats-json-path             | The path to the base stats.json file                                                                                | true     | string |
+| github-token                     | The Github token                                                                                                    | true     | string |
+| title                            | An optional addition to the title, which also helps key comments, useful if running more than 1 copy of this action | false    | string |
+| describe-assets                  | Option for asset description output. One of "all" (default), "changed-only", or "none".                             | false    | string |
+| total-increase-threshold-percent | If specified, comments will only be posted when the total bundle size increases by more than this percentage.       | false    | string |
 
 ## Example PR Comment
 

__tests__/threshold-check.test.ts

@@ -0,0 +1,360 @@
+import {expect, describe, test, jest, beforeEach} from '@jest/globals'
+import {
+  shouldPostComment,
+  totalSizeIncreasePercent
+} from '../src/threshold-check'
+import {WebpackStatsDiff} from '../src/types'
+import * as core from '@actions/core'
+
+jest.mock('@actions/core')
+const mockedCore = core as jest.Mocked<typeof core>
+
+describe('totalSizeIncreasePercent', () => {
+  test('calculates positive percentage increase correctly', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(totalSizeIncreasePercent(statsDiff)).toBe(10)
+  })
+
+  test('calculates negative percentage (decrease) correctly', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: -50,
+        diffPercentage: -10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 450, gzipSize: 225}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(totalSizeIncreasePercent(statsDiff)).toBe(-10)
+  })
+
+  test('returns 0 when there is no change', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 0,
+        diffPercentage: 0,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 500, gzipSize: 250}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(totalSizeIncreasePercent(statsDiff)).toBe(0)
+  })
+
+  test('returns Infinity when old size is 0 and new size is positive', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 100,
+        diffPercentage: Infinity,
+        old: {size: 0, gzipSize: 0},
+        new: {size: 100, gzipSize: 50}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(totalSizeIncreasePercent(statsDiff)).toBe(Infinity)
+  })
+
+  test('returns 0 when old size is 0 and diff is 0', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 0,
+        diffPercentage: 0,
+        old: {size: 0, gzipSize: 0},
+        new: {size: 0, gzipSize: 0}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(totalSizeIncreasePercent(statsDiff)).toBe(0)
+  })
+})
+
+describe('shouldPostComment', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+  })
+
+  test('returns true when no threshold is provided', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, undefined)).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns true when threshold is undefined', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff)).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns true when increase is above threshold', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '5')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns true when increase equals threshold', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '10')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns false when increase is below threshold', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '15')).toBe(false)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns false when size decreases (negative percentage)', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: -50,
+        diffPercentage: -10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 450, gzipSize: 225}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '5')).toBe(false)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns true when threshold is invalid (NaN) and logs warning', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, 'not-a-number')).toBe(true)
+    expect(mockedCore.warning).toHaveBeenCalledWith(
+      "Invalid total-increase-threshold-percent value: 'not-a-number'. Ignoring threshold."
+    )
+  })
+
+  test('returns true when threshold is empty string (treated as no threshold)', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    // Empty string is falsy, so it's treated same as undefined
+    expect(shouldPostComment(statsDiff, '')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('handles threshold with decimal values', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 50,
+        diffPercentage: 10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 550, gzipSize: 275}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '9.5')).toBe(true)
+    expect(shouldPostComment(statsDiff, '10.5')).toBe(false)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('returns true when increase is Infinity and threshold is set', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 100,
+        diffPercentage: Infinity,
+        old: {size: 0, gzipSize: 0},
+        new: {size: 100, gzipSize: 50}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '5')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('handles zero threshold (always posts)', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: 1,
+        diffPercentage: 0.2,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 501, gzipSize: 251}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    expect(shouldPostComment(statsDiff, '0')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+
+  test('handles negative threshold values', () => {
+    const statsDiff: WebpackStatsDiff = {
+      total: {
+        name: 'total',
+        diff: -50,
+        diffPercentage: -10,
+        old: {size: 500, gzipSize: 250},
+        new: {size: 450, gzipSize: 225}
+      },
+      added: [],
+      removed: [],
+      bigger: [],
+      smaller: [],
+      unchanged: []
+    }
+
+    // -10% >= -5% is false
+    expect(shouldPostComment(statsDiff, '-5')).toBe(false)
+    // -10% >= -15% is true
+    expect(shouldPostComment(statsDiff, '-15')).toBe(true)
+    expect(mockedCore.warning).not.toHaveBeenCalled()
+  })
+})

action.yml

@@ -27,6 +27,10 @@ inputs:
       If not provided, "all" is used (equivalent to "added removed bigger smaller unchanged")
     required: false
     default: 'all'
+  total-increase-threshold-percent:
+    description: |
+      If specified, comments will only be posted when the total bundle size increases by more than this percentage.
+    required: false
 
 runs:
   using: 'node20'