💥 change the AST of filters syntax (vuejs/eslint-plugin-vue#687)

Author: mysticatea

docs/ast.md

@@ -109,6 +109,18 @@ interface VSlotScopeExpression <: Expression {
     type: "VSlotScopeExpression"
     id: Pattern
 }
+
+interface VFilterSequenceExpression <: Expression {
+    type: "VFilterSequenceExpression"
+    expression: Expression
+    filters: [ VFilter ]
+}
+
+interface VFilter <: Node {
+    type: "VFilter"
+    callee: Identifier
+    arguments: [ Expression ]
+}
 ```
 
 - This is mustaches or directive values.
@@ -119,6 +131,7 @@ interface VSlotScopeExpression <: Expression {
 - `VForExpression` is an expression node like [ForInStatement] but it has an array as `left` property and does not have `body` property. This is the value of [`v-for` directives].
 - `VOnExpression` is an expression node like [BlockStatement] but it does not have braces. This is the value of [`v-on` directives] only if the `v-on` directive doesn't have that argument.
 - `VSlotScopeExpression` is an expression node like [VariableDeclarator]. This is the value of [`slot-scope` attribute] or the `scope` attribute of `<template>` elements.
+- `VFilterSequenceExpression` is an expression node for [Vue.js Filters](https://vuejs.org/v2/guide/filters.html) syntax.
 
 > Note: `vue-eslint-parser` transforms `v-for="(x, i) in list"` to `for(let [x, i] in list);` then gives the configured parser (`espree` by default) it. This implies that it needs the capability to parse ES2015 destructuring in order to parse [`v-for` directives].
 

src/ast/nodes.ts

@@ -28,6 +28,8 @@ export type Node =
     | VForExpression
     | VOnExpression
     | VSlotScopeExpression
+    | VFilterSequenceExpression
+    | VFilter
 
 //------------------------------------------------------------------------------
 // Script
@@ -688,6 +690,26 @@ export interface VSlotScopeExpression extends HasLocation, HasParent {
     id: ESLintPattern
 }
 
+/**
+ * The node of a filter sequence which is separated by `|`.
+ */
+export interface VFilterSequenceExpression extends HasLocation, HasParent {
+    type: "VFilterSequenceExpression"
+    parent: VExpressionContainer
+    expression: ESLintExpression
+    filters: VFilter[]
+}
+
+/**
+ * The node of a filter sequence which is separated by `|`.
+ */
+export interface VFilter extends HasLocation, HasParent {
+    type: "VFilter"
+    parent: VFilterSequenceExpression
+    callee: ESLintIdentifier
+    arguments: (ESLintExpression | ESLintSpreadElement)[]
+}
+
 /**
  * The union type of any nodes.
  */
@@ -722,6 +744,7 @@ export interface VExpressionContainer extends HasLocation, HasParent {
     parent: VDocumentFragment | VElement | VDirective
     expression:
         | ESLintExpression
+        | VFilterSequenceExpression
         | VForExpression
         | VOnExpression
         | VSlotScopeExpression

src/ast/traverse.ts

@@ -17,6 +17,8 @@ const KEYS = Evk.unionWith({
     VElement: ["startTag", "children", "endTag"],
     VEndTag: [],
     VExpressionContainer: ["expression"],
+    VFilter: ["callee", "arguments"],
+    VFilterSequenceExpression: ["expression", "filters"],
     VForExpression: ["left", "right"],
     VIdentifier: [],
     VLiteral: [],

src/common/location-calculator.ts

@@ -107,7 +107,7 @@ export class LocationCalculator {
      * Modify the location information of the given node with using the base offset and gaps of this calculator.
      * @param node The node to modify their location.
      */
-    public fixLocation(node: HasLocation): void {
+    public fixLocation<T extends HasLocation>(node: T): T {
         const range = node.range
         const loc = node.loc
         const gap0 = this._getGap(range[0])
@@ -129,6 +129,8 @@ export class LocationCalculator {
             }
             loc.end = this._getLocation(range[1])
         }
+
+        return node
     }
 
     /**