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📄 snapshot-diff.ts

📊 Analysis Summary

Metric	Count
🔧 Functions	4
📦 Imports	2
📊 Variables & Constants	2

📚 Table of Contents

• Imports
• Variables & Constants
• Functions

🛠️ File Location:

📂 packages/ast-spec/tests/util/snapshot-diff.ts

📦 Imports

Name	Source
format	@vitest/pretty-format
diff	@vitest/utils/diff

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Variables & Constants

Name	Type	Kind	Value	Exported
NO_DIFF_MESSAGE	"Compared values have no visual difference."	const	'Compared values have no visual difference.'	✗
OPTIONS	{ plugins: any[]; }	const	`{
plugins: [
NodeSerializer.serializer,
// by default vitest will quote the string with double quotes
// this means the diff string will have double quotes escaped and look ugly
// this is a single-quote string serializer which won't clash with the outer double quotes
// so we get a nicer looking diff because of it!
StringSerializer.serializer,
],
}`	✗

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Functions

identity(value: T): T

Code

function identity<T>(value: T): T {
  return value;
}

• Parameters:
• value: T
• Return Type: T

diffStrings(valueA: unknown, valueB: unknown, valueAName: string, valueBName: string): string | undefined

Code

function diffStrings(
  valueA: unknown,
  valueB: unknown,
  valueAName: string,
  valueBName: string,
): string | undefined {
  if (Object.is(valueA, valueB)) {
    return NO_DIFF_MESSAGE;
  }

  return diff(valueA, valueB, {
    expand: false,
    // we want to show the entire file in the diff
    // that way you don't have to try and figure out what lines map to which sections
    aAnnotation: valueAName,
    aColor: identity,
    bAnnotation: valueBName,
    bColor: identity,
    changeColor: identity,
    commonColor: identity,
    contextLines: Number.MAX_SAFE_INTEGER,
    patchColor: identity,
  });
}

• Parameters:
• valueA: unknown
• valueB: unknown
• valueAName: string
• valueBName: string
• Return Type: string | undefined
• Calls:
• Object.is
• diff (from @vitest/utils/diff)
• Internal Comments:

  // we want to show the entire file in the diff (x2)
  // that way you don't have to try and figure out what lines map to which sections (x2)
  

snapshotDiff(valueAName: string, valueA: unknown, valueBName: string, valueB: unknown): string

Code

export function snapshotDiff(
  valueAName: string,
  valueA: unknown,
  valueBName: string,
  valueB: unknown,
): string {
  const OPTIONS = {
    plugins: [
      NodeSerializer.serializer,
      // by default vitest will quote the string with double quotes
      // this means the diff string will have double quotes escaped and look ugly
      // this is a single-quote string serializer which won't clash with the outer double quotes
      // so we get a nicer looking diff because of it!
      StringSerializer.serializer,
    ],
  };

  const difference = diffStrings(
    format(valueA, OPTIONS),
    format(valueB, OPTIONS),
    valueAName,
    valueBName,
  );

  if (difference == null) {
    throw new Error('Unexpected null when diffing snapshots.');
  }

  return `Snapshot Diff:\n${difference}`;
}

• Parameters:
• valueAName: string
• valueA: unknown
• valueBName: string
• valueB: unknown
• Return Type: string
• Calls:
• diffStrings
• format (from @vitest/pretty-format)
• Internal Comments:

  // by default vitest will quote the string with double quotes (x2)
  // this means the diff string will have double quotes escaped and look ugly (x2)
  // this is a single-quote string serializer which won't clash with the outer double quotes (x2)
  // so we get a nicer looking diff because of it! (x2)
  

diffHasChanges(diff: string): boolean

Code

export function diffHasChanges(diff: string): boolean {
  return !diff.includes(NO_DIFF_MESSAGE);
}

• Parameters:
• diff: string
• Return Type: boolean
• Calls:
• diff.includes

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