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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 { DataType } from '../type.js';
import { valueToString } from '../util/pretty.js';
import { BigIntAvailable } from '../util/compat.js';
/**
* Dynamically compile the null values into an `isValid()` function whose
* implementation is a switch statement. Microbenchmarks in v8 indicate
* this approach is 25% faster than using an ES6 Map.
*
* @example
* console.log(createIsValidFunction([null, 'N/A', NaN]));
* `function (x) {
* if (x !== x) return false;
* switch (x) {
* case null:
* case "N/A":
* return false;
* }
* return true;
* }`
*
* @ignore
* @param nullValues
*/
export function createIsValidFunction<T extends DataType = any, TNull = any>(nullValues?: ReadonlyArray<TNull>) {
if (!nullValues || nullValues.length <= 0) {
// @ts-ignore
return function isValid(value: any) { return true; };
}
let fnBody = '';
const noNaNs = nullValues.filter((x) => x === x);
if (noNaNs.length > 0) {
fnBody = `
switch (x) {${noNaNs.map((x) => `
case ${valueToCase(x)}:`).join('')}
return false;
}`;
}
// NaN doesn't equal anything including itself, so it doesn't work as a
// switch case. Instead we must explicitly check for NaN before the switch.
if (nullValues.length !== noNaNs.length) {
fnBody = `if (x !== x) return false;\n${fnBody}`;
}
return new Function(`x`, `${fnBody}\nreturn true;`) as (value: T['TValue'] | TNull) => boolean;
}
/** @ignore */
function valueToCase(x: any) {
if (typeof x !== 'bigint') {
return valueToString(x);
} else if (BigIntAvailable) {
return `${valueToString(x)}n`;
}
return `"${valueToString(x)}"`;
}
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