All files / src/emulator/plugins BoundedHistoryIterator.js

100% Statements 12/12
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Press n or j to go to the next uncovered block, b, p or k for the previous block.

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/**
 * Makes a stack iterator for a point in history.
 *
 * Can go backwards and forwards through the history and is bounded by
 * the size of the stack.
 */
export default class BoundedHistoryIterator {
  constructor(historyStack, index = 0) {
    this.historyStack = historyStack.push('');
    this.index = index;
  }
 
  hasUp() {
    return this.index + 1 < this.historyStack.size;
  }
 
  up() {
    if (this.hasUp()) {
      this.index++;
    }
 
    return this.historyStack.get(this.index);
  }
 
  hasDown() {
    return this.index - 1 >= 0;
  }
 
  down() {
    if (this.hasDown()) {
      this.index--;
    }
 
    return this.historyStack.get(this.index);
  }
};