@bufbuild/cel/dist/esm/plan.js

A CEL evaluator for ECMAScript

// Copyright 2024-2025 Buf Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import { CheckedExprSchema, } from "@bufbuild/cel-spec/cel/expr/checked_pb.js";
import { ExprSchema, ParsedExprSchema, } from "@bufbuild/cel-spec/cel/expr/syntax_pb.js";
import { Planner } from "./planner.js";
import { create, isMessage } from "@bufbuild/protobuf";
import { celError, isCelError } from "./error.js";
import { withEvalContext } from "./eval.js";
import { unwrapAny } from "./value.js";
import { EMPTY_ACTIVATION, ObjectActivation } from "./activation.js";
const cache = new WeakMap();
/**
 * Creates an execution plan for a CEL expression and returns a reusable evaluation function.
 *
 * Planning analyzes the expression structure once, independent of runtime variable values.
 * The returned function can be called multiple times with different variable bindings.
 */
export function plan(env, expr) {
    // TODO(srikrsna): This can be avoided, if we refactor Planner into functions that use CelEnv directly.
    let planner = cache.get(env);
    if (planner === undefined) {
        planner = new Planner(env.dispatcher, env.registry, env.namespace);
        cache.set(env, planner);
    }
    let maybeExpr;
    if (isMessage(expr, CheckedExprSchema)) {
        maybeExpr = expr.expr;
    }
    else if (isMessage(expr, ParsedExprSchema)) {
        maybeExpr = expr.expr;
    }
    else {
        maybeExpr = expr;
    }
    const plan = planner.plan(maybeExpr ?? create(ExprSchema));
    const withContext = withEvalContext({ registry: env.registry }, {
        id: plan.id,
        eval(ctx) {
            try {
                let val = plan.eval(ctx);
                if (isCelError(val)) {
                    return val;
                }
                return unwrapAny(val);
            }
            catch (ex) {
                return celError(ex, plan.id);
            }
        },
    });
    return (ctx) => {
        return withContext.eval(ctx !== undefined ? new ObjectActivation(ctx) : EMPTY_ACTIVATION);
    };
}