Function VariableDeclaration

tools/acorn-optimizer.mjs:250–271

(node, _c)

          c(node.body);
        },
        VariableDeclaration(node, _c) {
          let removedHere = 0;
          node.declarations = node.declarations.filter((node) => {
            assert(node.type === 'VariableDeclarator');
            let keep = node.init && hasSideEffects(node.init);
            walkPattern(
              node.id,
              (value) => {
                keep ||= hasSideEffects(value);
              },
              (boundName) => {
                keep ||= !names.has(boundName);
              },
            );
            if (!keep) removedHere = 1;
            return keep;
          });
          removed += removedHere;
          if (node.declarations.length === 0) {
            emptyOut(node);
          }
        },
        ExpressionStatement(node, _c) {
          if (aggressive && !hasSideEffects(node)) {
            emptyOut(node);