@bufbuild/cel
Version:
A CEL evaluator for ECMAScript
91 lines (90 loc) • 3.2 kB
JavaScript
// 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 { DurationSchema } from "@bufbuild/protobuf/wkt";
import { create } from "@bufbuild/protobuf";
/**
* Create a new Duration, validating the fields are in range.
*/
export function createDuration(seconds, nanos) {
if (nanos >= 1000000000) {
seconds += BigInt(nanos / 1000000000);
nanos = nanos % 1000000000;
}
else if (nanos < 0) {
const negSeconds = Math.ceil(-nanos / 1000000000);
seconds -= BigInt(negSeconds);
nanos = nanos + negSeconds * 1000000000;
}
// Must fit in 64 bits of nanoseconds for compatibility with golang
const totalNanos = seconds * 1000000000n + BigInt(nanos);
if (totalNanos > 9223372036854775807n || totalNanos < -9223372036854775808n) {
throw new Error("duration out of range");
}
return create(DurationSchema, { seconds: seconds, nanos: nanos });
}
/**
* Parses a CEL duration string.
*
* A duration string is a possibly signed sequence of
* decimal numbers, each with optional fraction and a unit suffix,
* such as "300ms", "-1.5h" or "2h45m".
* Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
*/
export function parseDuration(str) {
// The regex grouping the number and the unit is:
const re = /([-+]?(?:\d+|\d+\.\d*|\d*\.\d+))(ns|us|µs|ms|s|m|h)/;
// Loop over the string matching the regex.
let seconds = 0n;
let nanos = 0;
let remaining = str;
while (remaining.length > 0) {
const match = re.exec(remaining);
if (match === null) {
throw badDurationStr("invalid syntax");
}
const [, numStr, unit] = match;
const num = Number(numStr);
if (Number.isNaN(num)) {
throw badDurationStr("invalid syntax");
}
switch (unit) {
case "ns":
nanos += num;
break;
case "us":
case "µs":
nanos += num * 1000;
break;
case "ms":
nanos += num * 1000000;
break;
case "s":
seconds += BigInt(num);
break;
case "m":
seconds += BigInt(num * 60);
break;
case "h":
seconds += BigInt(num * 3600);
break;
default:
throw badDurationStr("invalid syntax");
}
remaining = remaining.slice(match[0].length);
}
return createDuration(seconds, nanos);
}
function badDurationStr(e) {
return new Error(`Failed to parse duration: ${e}`);
}