1 | 'use strict';
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2 | const sliceAnsi = require('slice-ansi');
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3 | const stringWidth = require('string-width');
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4 |
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5 | function getIndexOfNearestSpace(string, index, shouldSearchRight) {
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6 | if (string.charAt(index) === ' ') {
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7 | return index;
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8 | }
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9 |
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10 | for (let i = 1; i <= 3; i++) {
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11 | if (shouldSearchRight) {
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12 | if (string.charAt(index + i) === ' ') {
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13 | return index + i;
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14 | }
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15 | } else if (string.charAt(index - i) === ' ') {
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16 | return index - i;
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17 | }
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18 | }
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19 |
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20 | return index;
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21 | }
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22 |
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23 | module.exports = (text, columns, options) => {
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24 | options = {
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25 | position: 'end',
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26 | preferTruncationOnSpace: false,
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27 | ...options
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28 | };
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29 |
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30 | const {position, space, preferTruncationOnSpace} = options;
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31 | let ellipsis = '…';
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32 | let ellipsisWidth = 1;
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33 |
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34 | if (typeof text !== 'string') {
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35 | throw new TypeError(`Expected \`input\` to be a string, got ${typeof text}`);
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36 | }
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37 |
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38 | if (typeof columns !== 'number') {
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39 | throw new TypeError(`Expected \`columns\` to be a number, got ${typeof columns}`);
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40 | }
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41 |
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42 | if (columns < 1) {
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43 | return '';
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44 | }
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45 |
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46 | if (columns === 1) {
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47 | return ellipsis;
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48 | }
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49 |
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50 | const length = stringWidth(text);
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51 |
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52 | if (length <= columns) {
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53 | return text;
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54 | }
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55 |
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56 | if (position === 'start') {
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57 | if (preferTruncationOnSpace) {
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58 | const nearestSpace = getIndexOfNearestSpace(text, length - columns + 1, true);
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59 | return ellipsis + sliceAnsi(text, nearestSpace, length).trim();
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60 | }
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61 |
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62 | if (space === true) {
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63 | ellipsis += ' ';
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64 | ellipsisWidth = 2;
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65 | }
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66 |
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67 | return ellipsis + sliceAnsi(text, length - columns + ellipsisWidth, length);
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68 | }
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69 |
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70 | if (position === 'middle') {
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71 | if (space === true) {
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72 | ellipsis = ' ' + ellipsis + ' ';
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73 | ellipsisWidth = 3;
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74 | }
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75 |
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76 | const half = Math.floor(columns / 2);
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77 |
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78 | if (preferTruncationOnSpace) {
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79 | const spaceNearFirstBreakPoint = getIndexOfNearestSpace(text, half);
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80 | const spaceNearSecondBreakPoint = getIndexOfNearestSpace(text, length - (columns - half) + 1, true);
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81 | return sliceAnsi(text, 0, spaceNearFirstBreakPoint) + ellipsis + sliceAnsi(text, spaceNearSecondBreakPoint, length).trim();
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82 | }
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83 |
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84 | return (
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85 | sliceAnsi(text, 0, half) +
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86 | ellipsis +
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87 | sliceAnsi(text, length - (columns - half) + ellipsisWidth, length)
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88 | );
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89 | }
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90 |
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91 | if (position === 'end') {
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92 | if (preferTruncationOnSpace) {
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93 | const nearestSpace = getIndexOfNearestSpace(text, columns - 1);
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94 | return sliceAnsi(text, 0, nearestSpace) + ellipsis;
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95 | }
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96 |
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97 | if (space === true) {
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98 | ellipsis = ' ' + ellipsis;
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99 | ellipsisWidth = 2;
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100 | }
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101 |
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102 | return sliceAnsi(text, 0, columns - ellipsisWidth) + ellipsis;
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103 | }
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104 |
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105 | throw new Error(`Expected \`options.position\` to be either \`start\`, \`middle\` or \`end\`, got ${position}`);
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106 | };
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