@adpt/core/dist/src/context.js

AdaptJS core library

"use strict";
/*
 * Copyright 2018-2019 Unbounded Systems, LLC
 *
 * 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.
 */
Object.defineProperty(exports, "__esModule", { value: true });
const tslib_1 = require("tslib");
const index_1 = require("./index");
const jsx_1 = require("./jsx");
const keys_1 = require("./keys");
const ld = tslib_1.__importStar(require("lodash"));
function createContext(defaultValue) {
    const stack = []; // class Provider
    function providerPush(provider) {
        stack.push(provider);
    }
    function providerPop() {
        stack.pop();
    }
    function currentVal() {
        if (stack.length > 0) {
            return stack[stack.length - 1].props.value;
        }
        return defaultValue;
    }
    // tslint:disable-next-line:no-shadowed-variable
    class Provider extends jsx_1.Component {
        constructor() {
            super(...arguments);
            this.cleanup = () => providerPop();
        }
        build() {
            const { children: child, key } = this.props;
            if ((child == null) || Array.isArray(child) || !jsx_1.isElement(child)) {
                throw new index_1.BuildNotImplemented(`A context Provider may only have a single child, which ` +
                    `must be a Component or SFC`);
            }
            providerPush(this);
            // If there was an explicit key set (i.e. not default), propagate
            // our key to our child, but don't overwrite any key
            // already on the child props.
            if (!key || keys_1.isDefaultKey(this.props) || "key" in child.props)
                return child;
            const _a = child.props, { children, handle } = _a, childProps = tslib_1.__rest(_a, ["children", "handle"]);
            return jsx_1.cloneElement(child, Object.assign({ key }, childProps), children);
        }
    }
    // tslint:disable-next-line:no-shadowed-variable
    class Consumer extends jsx_1.Component {
        build() {
            const { children } = this.props;
            if ((children == null) || Array.isArray(children) || !ld.isFunction(children)) {
                throw new index_1.BuildNotImplemented(`Children of a context Consumer must be a single function`);
            }
            return this.props.children(currentVal());
        }
    }
    const ret = {
        Provider,
        Consumer,
        currentVal: () => currentVal()
    };
    return ret;
}
exports.createContext = createContext;
function isContextImpl(context) {
    return ("currentVal" in context);
}
function useContext(context) {
    if (!isContextImpl(context))
        throw new Error("useContext context not a ContextImpl");
    return context.currentVal();
}
exports.useContext = useContext;
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