ptt-client/dist/utils/char.js

A Node client for fetching data from ptt.cc.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.dbcswidth = dbcswidth;
exports.getWidth = getWidth;
exports.indexOfWidth = indexOfWidth;
exports.substrWidth = substrWidth;

var _wcwidth = _interopRequireDefault(require("wcwidth"));

function dbcswidth(str) {
  return str.split('').reduce(function (sum, c) {
    return sum + (c.charCodeAt(0) > 255 ? 2 : 1);
  }, 0);
}
/**
* calculate width of string.
* @params {string} widthType - calculate width by wcwidth or String.length
* @params {string} str - string to calculate
*/


function getWidth(widthType, str) {
  switch (widthType) {
    case 'length':
      return str.length;

    case 'wcwidth':
      return (0, _wcwidth["default"])(str);

    case 'dbcs':
      return dbcswidth(str);

    default:
      throw new Error("Invalid widthType \"".concat(widthType, "\""));
  }
}
/**
* calculate the position that the prefix of string is a specific width
* @params {string} widthType - calculate width by wcwidth or String.length
* @params {string} str - string to calculate
* @params {number} width - the width of target string
*/


function indexOfWidth(widthType, str, width) {
  if (widthType === 'length') {
    return getWidth(widthType, str);
  }

  for (var i = 0; i <= str.length; i++) {
    if (getWidth(widthType, str.substr(0, i)) > width) {
      return i - 1;
    }
  }

  return str.length;
}
/**
* extract parts of string, beginning at the character at the specified position,
* and returns the specified width of characters. if the character is incomplete,
* it will be replaced by space.
* @params {string} widthType - calculate width by wcwidth or String.length
* @params {string} str - string to calculate
* @params {number} startWidth - the beginning position of string
* @params {number} width - the width of target string
*/


function substrWidth(widthType, str, startWidth, width) {
  var ignoreWidth = typeof width === 'undefined';
  var length = width;
  var start = startWidth;
  var prefixSpace = 0,
      suffixSpace = 0;

  if (widthType !== 'length') {
    start = indexOfWidth(widthType, str, startWidth);

    if (getWidth(widthType, str.substr(0, start)) < startWidth) {
      start += 1;
      prefixSpace = Math.max(getWidth(widthType, str.substr(0, start)) - startWidth, 0);
    }

    if (!ignoreWidth) {
      length = indexOfWidth(widthType, str.substr(start), width - prefixSpace);
      suffixSpace = Math.min(width, getWidth(widthType, str.substr(start))) - (prefixSpace + getWidth(widthType, str.substr(start, length)));
    }
  }

  var substr = ignoreWidth ? str.substr(start) : str.substr(start, length);
  return ' '.repeat(prefixSpace) + substr + ' '.repeat(suffixSpace);
}