Fix contextLines (which needs options merged) + update snapshots. (#8)

Author: ferrannp

README.md

@@ -78,6 +78,7 @@ snapshotDiff(valueA: any, valueB: any, options?: Options) => string
 ### Options
 * `expand: boolean` (default: `false`) – expand the diff, so the whole information is preserved
 * `colors: boolean` (default: `false`) – preserve color information from Jest diff
+* `contextLines: number` (default: 5) - number of context lines to be shown at the beginning and at the end of a snapshot
 
 ---
 

__tests__/__snapshots__/snapshotDiff.test.js.snap

@@ -4,19 +4,16 @@ exports[`can colorize diff 1`] = `
 "- First value
 + Second value
 
-  
-      some
-      some
-      some
-      some
-      some
-      some
-      some
-      not
-+     so
-      very
-      long
-      script"
+@@ -5,8 +5,9 @@
+     some
+     some
+     some
+     some
+     not
++    so
+     very
+     long
+     script"
 `;
 
 exports[`can expand diff 1`] = `
@@ -42,19 +39,23 @@ exports[`can use contextLines on diff 1`] = `
 "- First value
 + Second value
 
-  
-      some
-      some
-      some
-      some
-      some
-      some
-      some
-      not
-+     so
-      very
-      long
-      script"
+@@ -10,0 +10,1 @@
++    so"
+`;
+
+exports[`can use contextLines with React components 1`] = `
+"- <Component test=\\"say\\" />
++ <Component test=\\"my name\\" />
+
+@@ -6,1 +6,1 @@
+-    say
++    my name
+@@ -9,1 +9,1 @@
+-    say
++    my name
+@@ -32,1 +32,1 @@
+-    say
++    my name"
 `;
 
 exports[`collapses diffs and strips ansi by default 1`] = `

__tests__/snapshotDiff.test.js

@@ -129,7 +129,7 @@ test('can colorize diff', () => {
 });
 
 test('can use contextLines on diff', () => {
-  expect(snapshotDiff(a, b, {contextLines: 0})).toMatchSnapshot();
+  expect(snapshotDiff(a, b, { contextLines: 0 })).toMatchSnapshot();
 });
 
 test('diffs short strings', () => {
@@ -147,3 +147,11 @@ test('detects React components', () => {
     snapshotDiff(<Component test="say" />, <Component test="my name" />)
   ).toMatchSnapshot();
 });
+
+test('can use contextLines with React components', () => {
+  expect(
+    snapshotDiff(<Component test="say" />, <Component test="my name" />, {
+      contextLines: 0,
+    })
+  ).toMatchSnapshot();
+});

package.json

@@ -19,7 +19,7 @@
     "react-test-renderer": ">=15"
   },
   "dependencies": {
-    "jest-diff": "^20.0.3",
+    "jest-diff": "test",
     "pretty-format": "^20.0.3",
     "strip-ansi": "^4.0.0"
   },
@@ -31,7 +31,7 @@
     "eslint": "^4.3.0",
     "eslint-config-callstack-io": "^0.4.0",
     "flow-bin": "^0.51.0",
-    "jest": "^20.0.4",
+    "jest": "test",
     "react": "^15.6.1",
     "react-test-renderer": "^15.6.1"
   }

src/index.js

@@ -20,20 +20,17 @@ const defaultOptions = {
   contextLines: -1, // Forces to use default from Jest
 };
 
-const snapshotDiff = (
-  valueA: any,
-  valueB: any,
-  options?: Options = defaultOptions
-): string => {
+const snapshotDiff = (valueA: any, valueB: any, options?: Options): string => {
   let difference;
+  const mergedOptions = Object.assign({}, defaultOptions, options);
 
   if (isReactComponent(valueA) && isReactComponent(valueB)) {
-    difference = diffReactComponents(valueA, valueB, options);
+    difference = diffReactComponents(valueA, valueB, mergedOptions);
   } else {
-    difference = diffStrings(valueA, valueB, options);
+    difference = diffStrings(valueA, valueB, mergedOptions);
   }
 
-  if (!options.colors) {
+  if (!mergedOptions.colors) {
     const stripAnsi = require('strip-ansi');
     return stripAnsi(difference);
   }