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feat(transformer): support nullish-coalescing-operator plugin
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,56 @@ | ||
| mod nullish_coalescing_operator; | ||
| mod options; | ||
|
|
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| pub use nullish_coalescing_operator::NullishCoalescingOperator; | ||
| pub use options::ES2020Options; | ||
| use oxc_allocator::Vec; | ||
| use oxc_ast::ast::*; | ||
| use oxc_traverse::TraverseCtx; | ||
| use std::rc::Rc; | ||
|
|
||
| use crate::context::Ctx; | ||
|
|
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| #[allow(dead_code)] | ||
| pub struct ES2020<'a> { | ||
| ctx: Ctx<'a>, | ||
| options: ES2020Options, | ||
|
|
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| // Plugins | ||
| nullish_coalescing_operator: NullishCoalescingOperator<'a>, | ||
| } | ||
|
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| impl<'a> ES2020<'a> { | ||
| pub fn new(options: ES2020Options, ctx: Ctx<'a>) -> Self { | ||
| Self { | ||
| nullish_coalescing_operator: NullishCoalescingOperator::new(Rc::clone(&ctx)), | ||
| ctx, | ||
| options, | ||
| } | ||
| } | ||
|
|
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| pub fn transform_statements( | ||
| &mut self, | ||
| statements: &mut Vec<'a, Statement<'a>>, | ||
| ctx: &mut TraverseCtx<'a>, | ||
| ) { | ||
| if self.options.nullish_coalescing_operator { | ||
| self.nullish_coalescing_operator.transform_statements(statements, ctx); | ||
| } | ||
| } | ||
|
|
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| pub fn transform_statements_on_exit( | ||
| &mut self, | ||
| statements: &mut Vec<'a, Statement<'a>>, | ||
| ctx: &mut TraverseCtx<'a>, | ||
| ) { | ||
| if self.options.nullish_coalescing_operator { | ||
| self.nullish_coalescing_operator.transform_statements_on_exit(statements, ctx); | ||
| } | ||
| } | ||
|
|
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| pub fn transform_expression(&mut self, expr: &mut Expression<'a>, ctx: &mut TraverseCtx<'a>) { | ||
| if self.options.nullish_coalescing_operator { | ||
| self.nullish_coalescing_operator.transform_expression(expr, ctx); | ||
| } | ||
| } | ||
| } |
125 changes: 125 additions & 0 deletions
125
crates/oxc_transformer/src/es2020/nullish_coalescing_operator.rs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,125 @@ | ||
| use std::cell::Cell; | ||
|
|
||
| use oxc_semantic::{ReferenceFlag, SymbolFlags}; | ||
| use oxc_traverse::TraverseCtx; | ||
|
|
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| use oxc_allocator::Vec; | ||
| use oxc_ast::ast::*; | ||
| use oxc_span::SPAN; | ||
| use oxc_syntax::operator::{AssignmentOperator, BinaryOperator, LogicalOperator}; | ||
|
|
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| use crate::context::Ctx; | ||
|
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| /// ES2020: Nullish Coalescing Operator | ||
| /// | ||
| /// References: | ||
| /// * <https://babeljs.io/docs/babel-plugin-transform-nullish-coalescing-operator> | ||
| /// * <https://github.com/babel/babel/tree/main/packages/babel-plugin-transform-nullish-coalescing-operator> | ||
| pub struct NullishCoalescingOperator<'a> { | ||
| _ctx: Ctx<'a>, | ||
| var_declarations: std::vec::Vec<Vec<'a, VariableDeclarator<'a>>>, | ||
| } | ||
|
|
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| impl<'a> NullishCoalescingOperator<'a> { | ||
| pub fn new(ctx: Ctx<'a>) -> Self { | ||
| Self { _ctx: ctx, var_declarations: vec![] } | ||
| } | ||
|
|
||
| pub fn transform_statements( | ||
| &mut self, | ||
| _statements: &mut Vec<'a, Statement<'a>>, | ||
| ctx: &mut TraverseCtx<'a>, | ||
| ) { | ||
| self.var_declarations.push(ctx.ast.vec()); | ||
| } | ||
|
|
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| pub fn transform_statements_on_exit( | ||
| &mut self, | ||
| statements: &mut Vec<'a, Statement<'a>>, | ||
| ctx: &mut TraverseCtx<'a>, | ||
| ) { | ||
| if let Some(declarations) = self.var_declarations.pop() { | ||
| if declarations.is_empty() { | ||
| return; | ||
| } | ||
| let variable = ctx.ast.alloc_variable_declaration( | ||
| SPAN, | ||
| VariableDeclarationKind::Var, | ||
| declarations, | ||
| false, | ||
| ); | ||
| statements.insert(0, Statement::VariableDeclaration(variable)); | ||
| } | ||
| } | ||
|
|
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| fn create_new_var_with_expression( | ||
| &mut self, | ||
| expr: &Expression<'a>, | ||
| ctx: &mut TraverseCtx<'a>, | ||
| ) -> IdentifierReference<'a> { | ||
| // Add `var name` to scope | ||
| let name = match expr { | ||
| Expression::Identifier(ref ident) => ident.name.as_str(), | ||
| _ => "nullish_coalescing_operator", | ||
| }; | ||
| let symbol_id = | ||
| ctx.generate_uid_in_current_scope(name, SymbolFlags::FunctionScopedVariable); | ||
| let symbol_name = ctx.ast.atom(ctx.symbols().get_name(symbol_id)); | ||
|
|
||
| { | ||
| // var _name; | ||
| let binding_identifier = BindingIdentifier { | ||
| span: SPAN, | ||
| name: symbol_name.clone(), | ||
| symbol_id: Cell::new(Some(symbol_id)), | ||
| }; | ||
| let kind = VariableDeclarationKind::Var; | ||
| let id = ctx.ast.binding_pattern_kind_from_binding_identifier(binding_identifier); | ||
| let id = ctx.ast.binding_pattern(id, None::<TSTypeAnnotation<'_>>, false); | ||
| self.var_declarations | ||
| .last_mut() | ||
| .unwrap() | ||
| .push(ctx.ast.variable_declarator(SPAN, kind, id, None, false)); | ||
| }; | ||
|
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| ctx.create_reference_id(SPAN, symbol_name, Some(symbol_id), ReferenceFlag::Read) | ||
| } | ||
|
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| pub fn transform_expression(&mut self, expr: &mut Expression<'a>, ctx: &mut TraverseCtx<'a>) { | ||
| // left ?? right | ||
| let Expression::LogicalExpression(logical_expr) = expr else { return }; | ||
| if logical_expr.operator != LogicalOperator::Coalesce { | ||
| return; | ||
| } | ||
|
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| let reference; | ||
| let assignment; | ||
|
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| // skip creating extra reference when `left` is static | ||
| if ctx.symbols().is_static(&logical_expr.left) { | ||
| reference = ctx.ast.copy(&logical_expr.left); | ||
| assignment = ctx.ast.copy(&logical_expr.left); | ||
| } else { | ||
| let ident = self.create_new_var_with_expression(&logical_expr.left, ctx); | ||
| reference = ctx.ast.expression_from_identifier_reference(ident.clone()); | ||
| let left = AssignmentTarget::from( | ||
| ctx.ast.simple_assignment_target_from_identifier_reference(ident), | ||
| ); | ||
| let right = ctx.ast.copy(&logical_expr.left); | ||
| assignment = | ||
| ctx.ast.expression_assignment(SPAN, AssignmentOperator::Assign, left, right); | ||
| }; | ||
|
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| let op = BinaryOperator::StrictInequality; | ||
| let null = ctx.ast.expression_null_literal(SPAN); | ||
| let left = ctx.ast.expression_binary(SPAN, ctx.ast.copy(&assignment), op, null); | ||
|
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| let right = ctx.ast.expression_binary(SPAN, ctx.ast.copy(&reference), op, ctx.ast.void_0()); | ||
|
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| let test = ctx.ast.expression_logical(SPAN, left, LogicalOperator::And, right); | ||
|
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| let right = ctx.ast.move_expression(&mut logical_expr.right); | ||
|
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| *expr = ctx.ast.expression_conditional(SPAN, test, reference, right); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,16 @@ | ||
| use serde::Deserialize; | ||
|
|
||
| #[derive(Debug, Default, Clone, Deserialize)] | ||
| #[serde(default, rename_all = "camelCase", deny_unknown_fields)] | ||
| pub struct ES2020Options { | ||
| #[serde(skip)] | ||
| pub nullish_coalescing_operator: bool, | ||
| } | ||
|
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| impl ES2020Options { | ||
| #[must_use] | ||
| pub fn with_nullish_coalescing_operator(mut self, enable: bool) -> Self { | ||
| self.nullish_coalescing_operator = enable; | ||
| self | ||
| } | ||
| } |
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