adaptive-expressions
Version:
Common Expression Language
59 lines • 2.16 kB
JavaScript
;
/**
* @module adaptive-expressions
*/
/**
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Take = void 0;
const expressionEvaluator_1 = require("../expressionEvaluator");
const expressionType_1 = require("../expressionType");
const functionUtils_1 = require("../functionUtils");
const returnType_1 = require("../returnType");
/**
* Return items from the front of an array or take the specific prefix from a string.
*/
class Take extends expressionEvaluator_1.ExpressionEvaluator {
/**
* Initializes a new instance of the [Take](xref:adaptive-expressions.Take) class.
*/
constructor() {
super(expressionType_1.ExpressionType.Take, Take.evaluator, returnType_1.ReturnType.Array | returnType_1.ReturnType.String, Take.validator);
}
/**
* @private
*/
static evaluator(expression, state, options) {
let result;
const { value: arr, error: childrenError } = expression.children[0].tryEvaluate(state, options);
let error = childrenError;
if (!error) {
if (Array.isArray(arr) || typeof arr === 'string') {
let start;
const startExpr = expression.children[1];
({ value: start, error } = startExpr.tryEvaluate(state, options));
if (!error && !Number.isInteger(start)) {
error = `${startExpr} is not an integer.`;
}
if (!error) {
start = Math.max(start, 0);
result = arr.slice(0, start);
}
}
else {
error = `${expression.children[0]} is not array or string.`;
}
}
return { value: result, error };
}
/**
* @private
*/
static validator(expression) {
functionUtils_1.FunctionUtils.validateOrder(expression, [], returnType_1.ReturnType.Array | returnType_1.ReturnType.String, returnType_1.ReturnType.Number);
}
}
exports.Take = Take;
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