@onekuma/seq/dist/index.mjs

OneKuma Sequence Collection

import { Option } from '@onekuma/option';

class BaseSeq {
}
class Seq extends BaseSeq {
  constructor(forEach, done = false) {
    super();
    this.forEach = forEach;
    this.done = done;
  }
  static of(...args) {
    return this.from(args);
  }
  static from(arr) {
    if (Array.isArray(arr)) {
      let i = 0;
      return new Seq((consume) => {
        if (i < arr.length) {
          consume(arr[i++]);
          return true;
        } else {
          return false;
        }
      });
    } else {
      return new Seq((consume) => {
        const cur = arr.next();
        if (!cur.done) {
          consume(cur.value);
          return true;
        } else {
          return false;
        }
      });
    }
  }
  static range(...args) {
    if (args.length === 1 || args.length === 2) {
      const n = args[args.length - 1];
      let i = args.length === 1 ? 0 : args[0];
      return new Seq((consume) => {
        if (i < n) {
          consume(i++);
          return true;
        } else {
          return false;
        }
      });
    } else {
      return Seq.of();
    }
  }
  map(fn) {
    return new Seq((consume) => this.forEach((t) => consume(fn(t))));
  }
  enumerate() {
    let i = 0;
    return this.map((e) => [i++, e]);
  }
  filter(predicate) {
    return new Seq((consume) => this.forEach((t) => predicate(t) && consume(t)));
  }
  filterDef() {
    return this.filter((e) => e !== void 0 && e !== null);
  }
  catch(handler) {
    return new Seq((consume) => {
      try {
        return this.forEach((t) => consume(t));
      } catch (error) {
        handler && handler(error);
        return true;
      }
    });
  }
  first() {
    let elem = Option.none();
    this.forEach((t) => elem = Option.some(t));
    return elem;
  }
  last() {
    let elem = Option.none();
    while (this.forEach((t) => elem = Option.some(t)))
      ;
    return elem;
  }
  take(count) {
    let i = 0;
    return new Seq((consume) => {
      if (i < count) {
        i++;
        return this.forEach((t) => consume(t));
      } else {
        return false;
      }
    });
  }
  drop(count) {
    let i = 0;
    return new Seq(
      (consume) => this.forEach((t) => {
        if (i < count) {
          i++;
        } else {
          consume(t);
        }
      })
    );
  }
  static chain(...args) {
    if (args.length > 0) {
      return args[0].concat(...args.slice(1));
    } else {
      return Seq.of();
    }
  }
  concat(...args) {
    let i = 0;
    return new Seq((consume) => {
      while (this.forEach((t) => consume(t)))
        ;
      while (i < args.length) {
        let cont = args[i].forEach((t) => consume(t));
        if (cont) {
          return true;
        }
        i++;
      }
      return false;
    });
  }
  append(...args) {
    return this.concat(Seq.of(...args));
  }
  *[Symbol.iterator]() {
    let elem = void 0;
    while (this.forEach((t) => elem = t)) {
      yield elem;
    }
  }
  async() {
    const it = this[Symbol.iterator]();
    return new AsyncSeq(async (consume) => {
      const cur = it.next();
      if (!cur.done) {
        await consume(cur.value);
        return true;
      } else {
        return false;
      }
    }, this.done);
  }
  // API that closees this sequence
  reduce(reducer) {
    this.close();
    let f = this.first();
    if (f.isNone)
      return f;
    let acc = f.value;
    while (this.forEach((t) => acc = reducer(acc, t)))
      ;
    return Option.some(acc);
  }
  fold(initial, reducer) {
    this.close();
    let acc = initial;
    while (this.forEach((t) => acc = reducer(acc, t)))
      ;
    return acc;
  }
  async parallel(fn) {
    const arr = this.toArray();
    return await Promise.all(arr.map((el) => fn(el)));
  }
  toArray() {
    this.close();
    const arr = [];
    while (this.forEach((t) => arr.push(t)))
      ;
    return arr;
  }
  close() {
    if (this.done) {
      throw new SeqError();
    }
    this.done = true;
  }
}
class AsyncSeq extends BaseSeq {
  constructor(forEach, done = false) {
    super();
    this.forEach = forEach;
    this.done = done;
  }
  static of(...args) {
    return this.from(args);
  }
  static from(arr) {
    return Seq.from(arr).async();
  }
  map(fn) {
    return new AsyncSeq(
      async (consume) => await this.forEach(async (t) => await consume(await fn(t)))
    );
  }
  filter(fn) {
    return new AsyncSeq(
      async (consume) => await this.forEach(async (t) => {
        if (await fn(t)) {
          await consume(t);
        }
      })
    );
  }
  // API that closees this sequence
  async toArray() {
    this.close();
    const arr = [];
    while (await this.forEach(async (t) => {
      arr.push(t);
    }))
      ;
    return arr;
  }
  close() {
    if (this.done) {
      throw new SeqError();
    }
    this.done = true;
  }
}
class SeqError extends Error {
  constructor() {
    super("This seq has been consumed");
  }
}
function range(...args) {
  if (args.length === 1) {
    const n = Array.isArray(args[0]) ? args[0].length : args[0];
    let i = 0;
    return new Seq((consume) => {
      if (i < n) {
        consume(i++);
        return true;
      } else {
        return false;
      }
    });
  } else if (args.length === 2) {
    let i = args[0];
    const n = args[1];
    if (args[0] <= args[1]) {
      return new Seq((consume) => {
        if (i < n) {
          consume(i++);
          return true;
        } else {
          return false;
        }
      });
    } else {
      return new Seq((consume) => {
        if (i > n) {
          consume(i--);
          return true;
        } else {
          return false;
        }
      });
    }
  } else if (args.length === 3) {
    let i = args[0];
    const n = args[1];
    const step = args[2];
    if (args[0] < args[1]) {
      return new Seq((consume) => {
        if (i < n) {
          consume(i);
          i += step;
          return true;
        } else {
          return false;
        }
      });
    } else if (args[0] > args[1]) {
      return new Seq((consume) => {
        if (i > n) {
          consume(i);
          i -= step;
          return true;
        } else {
          return false;
        }
      });
    } else {
      return Seq.of();
    }
  } else {
    return Seq.of();
  }
}

export { AsyncSeq, Seq, SeqError, range };