@andrew_l/context/dist/index.mjs

Like composition api but for Node.

import { noop, isPromise, catchError, captureStackTrace, isFunction, assert } from '@andrew_l/toolkit';

let idSec = 0;
let ALS;
let currentScope = null;
import('node:async_hooks').then((r) => {
  ALS = new r.AsyncLocalStorage();
}).catch(noop);
class Scope {
  constructor(detached = false) {
    this.detached = detached;
    this.id = ++idSec;
    if (!detached) {
      this.parent = getCurrentScope();
    }
  }
  /**
   * @internal
   */
  id;
  /**
   * @internal
   */
  providers = /* @__PURE__ */ new Map();
  /**
   * @internal
   */
  parent = null;
  /**
   * @internal
   */
  cleanups = [];
  /**
   * @internal
   */
  _activeRuns = 0;
  run(fn) {
    this._activeRuns++;
    const onComplete = ([err, result]) => {
      this._activeRuns--;
      if (this._activeRuns === 0) {
        this.stop();
      }
      if (err) {
        throw err;
      }
      return result;
    };
    const r = runInScope(this, fn);
    if (isPromise(r)) {
      return r.then(onComplete);
    }
    return onComplete(r);
  }
  stop() {
    for (let i = 0, l = this.cleanups.length; i < l; i++) {
      this.cleanups[i]();
    }
    this.cleanups.length = 0;
  }
  get active() {
    return this._activeRuns > 0;
  }
}
function createScope(detached) {
  return new Scope(detached);
}
function getCurrentScope() {
  if (ALS) {
    return ALS.getStore() ?? null;
  }
  return currentScope;
}
function setCurrentScope(scope) {
  if (ALS) {
    ALS.enterWith(scope);
  } else {
    currentScope = scope;
  }
}
function runInScope(scope, fn) {
  if (ALS) {
    return catchError(() => ALS.run(scope, fn));
  }
  const prevScope = getCurrentScope();
  const onComplete = ([err, result2]) => {
    if (prevScope) {
      setCurrentScope(prevScope);
    } else {
      unsetCurrentScope();
    }
    return [err, result2];
  };
  const result = catchError(fn);
  if (isPromise(result)) {
    return result.then(onComplete);
  }
  return onComplete(result);
}
const unsetCurrentScope = () => {
  if (ALS) {
    ALS.enterWith(null);
  } else {
    currentScope = null;
  }
};

function provide(key, value, enterWith) {
  let currentScope = getCurrentScope();
  if (!currentScope) {
    if (enterWith) {
      currentScope = new Scope();
      setCurrentScope(currentScope);
    } else {
      console.warn(
        `provide() is called when there is no active scope to be associated with.
` + captureStackTrace(provide)
      );
      return;
    }
  }
  currentScope.providers.set(key, value);
}
function inject(key, defaultValue) {
  let currentScope = getCurrentScope();
  if (!currentScope) {
    console.warn(
      `inject() is called when there is no active scope to be associated with.
` + captureStackTrace(inject)
    );
    return;
  }
  const handled = /* @__PURE__ */ new WeakSet();
  let value;
  do {
    value = currentScope.providers.get(key);
    handled.add(currentScope);
    currentScope = currentScope.parent;
  } while (currentScope && value === void 0 && !handled.has(currentScope));
  if (value === void 0 && defaultValue !== void 0) {
    value = isFunction(defaultValue) ? defaultValue() : defaultValue;
  }
  return value;
}
function hasInjectionContext() {
  return !!getCurrentScope();
}

function createContext(providerName, contextName) {
  const symbolDescription = typeof providerName === "string" && !contextName ? `${providerName}Context` : contextName;
  const injectionKey = Symbol(symbolDescription);
  const injectContext = (fallback) => {
    const context = inject(injectionKey, fallback);
    if (context) return context;
    if (context === null) return context;
    throw new Error(
      `Injection \`${injectionKey.toString()}\` not found. Must be used within ${Array.isArray(providerName) ? `one of the following providers: ${providerName.join(", ")}` : `\`${providerName}\``}`
    );
  };
  const provideContext = (contextValue) => {
    provide(injectionKey, contextValue);
    return contextValue;
  };
  return [injectContext, provideContext];
}

function onScopeDispose(fn) {
  const activeScope = getCurrentScope();
  assert.ok(
    activeScope,
    "onScopeDispose() is called when there is no active scope to be associated with." + captureStackTrace(onScopeDispose)
  );
  activeScope.cleanups.push(fn);
}

function withContext(fn, detached = false) {
  return function(...args) {
    const scope = createScope(detached);
    return scope.run(fn.bind(this, ...args));
  };
}
function runWithContext(fn, isolated = false) {
  return withContext(fn, isolated)();
}
function bindContext(fn) {
  const activeScope = getCurrentScope();
  assert.ok(
    activeScope,
    "bindContext() is called when there is no active scope to be associated with."
  );
  return () => activeScope.run(fn);
}

export { bindContext, createContext, getCurrentScope, hasInjectionContext, inject, onScopeDispose, provide, runWithContext, withContext };
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