Add directive property to follow ESTree

ESTree added `directive` property to `ExpressionStatement` which is in directive prologue: estree/estree@b3de58c...1da8e60

src/expression.js

@@ -734,6 +734,7 @@ pp.parseFunctionBody = function(node, isArrowFunction) {
     this.checkParams(node, !oldStrict && !useStrict && !isArrowFunction && this.isSimpleParamList(node.params))
     node.body = this.parseBlock(false)
     node.expression = false
+    this.adaptDirectivePrologue(node.body.body)
     this.labels = oldLabels
   }
   this.exitFunctionScope()

src/loose/expression.js

@@ -514,8 +514,8 @@ lp.parseMethod = function(isGenerator, isAsync) {
     node.async = !!isAsync
   this.inAsync = node.async
   node.params = this.parseFunctionParams()
-  node.expression = this.options.ecmaVersion >= 6 && this.tok.type !== tt.braceL
-  node.body = node.expression ? this.parseMaybeAssign() : this.parseBlock()
+  node.body = this.parseBlock()
+  this.toks.adaptDirectivePrologue(node.body.body)
   this.inAsync = oldInAsync
   return this.finishNode(node, "FunctionExpression")
 }
@@ -528,7 +528,12 @@ lp.parseArrowExpression = function(node, params, isAsync) {
   this.inAsync = node.async
   node.params = this.toAssignableList(params, true)
   node.expression = this.tok.type !== tt.braceL
-  node.body = node.expression ? this.parseMaybeAssign() : this.parseBlock()
+  if (node.expression) {
+    node.body = this.parseMaybeAssign()
+  } else {
+    node.body = this.parseBlock()
+    this.toks.adaptDirectivePrologue(node.body.body)
+  }
   this.inAsync = oldInAsync
   return this.finishNode(node, "ArrowFunctionExpression")
 }

src/loose/statement.js

@@ -8,6 +8,7 @@ lp.parseTopLevel = function() {
   let node = this.startNodeAt(this.options.locations ? [0, getLineInfo(this.input, 0)] : 0)
   node.body = []
   while (this.tok.type !== tt.eof) node.body.push(this.parseStatement())
+  this.toks.adaptDirectivePrologue(node.body)
   this.last = this.tok
   if (this.options.ecmaVersion >= 6) {
     node.sourceType = this.options.sourceType
@@ -330,6 +331,7 @@ lp.parseFunction = function(node, isStatement, isAsync) {
   this.inAsync = node.async
   node.params = this.parseFunctionParams()
   node.body = this.parseBlock()
+  this.toks.adaptDirectivePrologue(node.body.body)
   this.inAsync = oldInAsync
   return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression")
 }

src/statement.js

@@ -21,6 +21,7 @@ pp.parseTopLevel = function(node) {
     let stmt = this.parseStatement(true, true, exports)
     node.body.push(stmt)
   }
+  this.adaptDirectivePrologue(node.body)
   this.next()
   if (this.options.ecmaVersion >= 6) {
     node.sourceType = this.options.sourceType
@@ -760,3 +761,19 @@ pp.parseImportSpecifiers = function() {
   }
   return nodes
 }
+
+// Set `ExpressionStatement#directive` property for directive prologues.
+pp.adaptDirectivePrologue = function(statements) {
+  for (let i = 0; i < statements.length && this.isDirectiveCandidate(statements[i]); ++i) {
+    statements[i].directive = statements[i].expression.raw.slice(1, -1)
+  }
+}
+pp.isDirectiveCandidate = function(statement) {
+  return (
+    statement.type === "ExpressionStatement" &&
+    statement.expression.type === "Literal" &&
+    typeof statement.expression.value === "string" &&
+    // Reject parenthesized strings.
+    (this.input[statement.start] === "\"" || this.input[statement.start] === "'")
+  )
+}

test/run.js

@@ -9,6 +9,7 @@
     require("./tests-asyncawait.js");
     require("./tests-trailing-commas-in-func.js");
     require("./tests-template-literal-revision.js");
+    require("./tests-directive.js");
     acorn = require("../dist/acorn")
     require("../dist/acorn_loose")
   } else {