feat(utils): slice

Signed-off-by: Lexus Drumgold <[email protected]>

src/utils/__tests__/slice.spec.ts

@@ -0,0 +1,61 @@
+/**
+ * @file Unit Tests - slice
+ * @module esast-util-attach-comments/utils/tests/unit/slice
+ */
+
+import type { State } from '#src/types'
+import type { NewExpression } from 'estree'
+import testSubject from '../slice'
+
+describe('unit:utils/slice', () => {
+  let node: NewExpression
+  let state: State
+
+  beforeAll(() => {
+    state = {
+      comments: [
+        {
+          position: {
+            end: { column: 33, line: 11, offset: 411 },
+            start: { column: 18, line: 11, offset: 396 }
+          },
+          type: 'Block',
+          value: ' @__PURE__ '
+        },
+        {
+          position: {
+            end: { column: 27, line: 14, offset: 535 },
+            start: { column: 12, line: 14, offset: 520 }
+          },
+          type: 'Block',
+          value: ' @__PURE__ '
+        }
+      ],
+      index: 0
+    }
+
+    node = {
+      arguments: [],
+      callee: {
+        name: 'Set',
+        position: {
+          end: { column: 41, line: 11, offset: 419 },
+          start: { column: 38, line: 11, offset: 416 }
+        },
+        type: 'Identifier'
+      },
+      position: {
+        end: { column: 43, line: 11, offset: 421 },
+        start: { column: 34, line: 11, offset: 412 }
+      },
+      type: 'NewExpression'
+    }
+  })
+
+  it('should return slice from state.comments', () => {
+    expect(testSubject(state, node))
+      .to.be.an('array')
+      .of.length(1)
+      .with.deep.ordered.members([state.comments[0]])
+  })
+})

src/utils/index.ts

@@ -5,3 +5,4 @@
 
 export { default as compare } from './compare'
 export { default as keycheck } from './keycheck'
+export { default as slice } from './slice'

src/utils/slice.ts

@@ -0,0 +1,48 @@
+/**
+ * @file Utilities - slice
+ * @module esast-util-attach-comments/utils/slice
+ */
+
+import type { State } from '#src/types'
+import type { Comment, Node } from 'estree'
+import compare from './compare'
+
+/**
+ * Get a comments slice.
+ *
+ * @see {@linkcode Comment}
+ * @see {@linkcode Node}
+ * @see {@linkcode State}
+ *
+ * @internal
+ *
+ * @this {void}
+ *
+ * @param {State} state - Visitor state
+ * @param {Node} node - Node being visited
+ * @param {boolean?} [trailing] - Trailing comments slice?
+ * @return {Comment[]} Slice from `state.comments`
+ */
+function slice(
+  this: void,
+  state: State,
+  node: Node,
+  trailing?: boolean
+): Comment[] {
+  /**
+   * Slice result.
+   *
+   * @const {Comment[]} result
+   */
+  const result: Comment[] = []
+
+  // get slice
+  while (
+    state.comments[state.index] &&
+    compare(state.comments[state.index]!, node, trailing) < 1
+  ) result.push(state.comments[state.index++]!)
+
+  return result
+}
+
+export default slice