Function handleFunction

tools/acorn-optimizer.mjs:292–324

(node, c, defun)

    }

    function handleFunction(node, c, defun) {
      // defun names matter - function names (the y in var x = function y() {..}) are just for stack traces.
      if (defun) {
        ensureData(scopes[scopes.length - 1], node.id.name).def = 1;
      }
      const scope = {};
      scopes.push(scope);
      for (const param of node.params) {
        walkPattern(param, c, (name) => {
          ensureData(scope, name).def = 1;
          scope[name].param = 1;
        });
      }
      c(node.body);
      // we can ignore self-references, i.e., references to ourselves inside
      // ourselves, for named defined (defun) functions
      const ownName = defun ? node.id.name : '';
      const names = new Set();
      for (const name in scopes.pop()) {
        if (name === ownName) continue;
        const data = scope[name];
        if (data.use && !data.def) {
          // this is used from a higher scope, propagate the use down
          ensureData(scopes[scopes.length - 1], name).use = 1;
          continue;
        }
        if (data.def && !data.use && !data.param) {
          // this is eliminatable!
          names.add(name);
        }
      }
      cleanUp(node.body, names);
    }

    recursiveWalk(ast, {
      VariableDeclarator(node, c) {