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7 | class Scrollnav {
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8 | constructor(menu, content, options) {
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9 | if (!(menu instanceof HTMLElement))
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10 | throw Error('scrollnav: invalid <menu> element provided');
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11 | if (!(content instanceof HTMLElement))
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12 | throw Error('scrollnav: invalid <content> element provided');
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13 | if (typeof options !== 'object') options = {};
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14 |
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15 | if (Scrollnav.prototype.INITIATED)
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16 | throw Error('scrollnav: only 1 instance per page allowed!');
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17 | Scrollnav.prototype.INITIATED = true;
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18 |
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19 | this.ID;
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20 | this.ticking = [];
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21 | this._menu = menu;
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22 | this._content = content;
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23 | this._links = [];
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24 | this._sections = [...this._menu.querySelectorAll('ul li a')].reduce(
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25 | (list, link) => {
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26 | if (!link.getAttribute('href').startsWith('#')) return list;
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27 | let section = this._content.querySelector(link.getAttribute('href'));
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28 | if (!section) return list;
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29 |
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30 | this._links.push(link);
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31 | link.onclick = async ev => {
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32 | ev.preventDefault();
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33 | const ID = link.getAttribute('href');
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34 | this.highlightHeading(ID);
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35 | this.scrollContent(ID);
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36 | this.setHash(ID);
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37 | };
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38 |
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39 | return [...list, section];
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40 | },
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41 | []
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42 | );
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43 | this._topheading = `#${this._sections[0].id}`;
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44 |
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45 | window.onhashchange = this.watchHash.bind(this);
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46 | this._content.addEventListener('scroll', ev => {
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47 | if (!this.ticking.length) {
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48 | this.ticking.push(1);
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49 | requestAnimationFrame(() => {
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50 | this.watchScroll(ev);
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51 | this.ticking.pop();
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52 | });
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53 | }
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54 | });
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55 |
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56 | this.set(null, false);
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57 | return this;
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58 | }
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59 |
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60 | set(ID, smooth) {
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61 | this.highlightHeading(ID);
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62 | this.scrollMenu(ID, smooth);
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63 | this.scrollContent(ID, smooth);
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64 | this.setHash(ID);
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65 | }
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66 |
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67 | parseID(ID) {
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68 | if (!ID || typeof ID !== 'string') ID = location.hash || this._topheading;
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69 | if (!ID.startsWith('#')) ID = `#${ID}`;
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70 | if (!this._links.find(el => el.getAttribute('href') === ID))
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71 | ID = this._topheading;
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72 | this.ID = ID;
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73 | return ID;
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74 | }
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75 | highlightHeading(ID) {
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76 | this.parseID(ID);
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77 | this._links.forEach(el =>
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78 | el.getAttribute('href') === this.ID
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79 | ? el.classList.add('active')
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80 | : el.classList.remove('active')
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81 | );
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82 | return true;
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83 | }
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84 |
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85 | watchHash(ev) {
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86 | ev.preventDefault();
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87 | if (ev.newURL !== ev.oldURL) {
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88 | this.set();
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89 | }
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90 | }
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91 | setHash(ID) {
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92 | if (!history.replaceState) return false;
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93 | this.parseID(ID);
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94 | history.replaceState(null, null, ID === this._topheading ? '#' : this.ID);
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95 | return true;
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96 | }
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97 |
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98 | scrollContent(ID, smooth = true) {
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99 | this.ticking.push(1);
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100 | this.parseID(ID);
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101 | let offset = this._sections.find(el => `#${el.id}` === this.ID).offsetTop;
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102 | if (offset < this._content.clientHeight / 2) offset = 0;
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103 | this._content.scroll({
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104 | top: offset,
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105 | behavior: smooth ? 'smooth' : 'auto'
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106 | });
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107 | setTimeout(() => this.ticking.pop(), 1000);
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108 | return true;
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109 | }
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110 | scrollMenu(ID, smooth = true) {
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111 | this.parseID(ID);
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112 | let offset = this._links.find(el => el.getAttribute('href') === this.ID)
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113 | .offsetTop;
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114 | if (offset < this._menu.clientHeight / 2) offset = 0;
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115 | this._menu.scroll({
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116 | top: offset,
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117 | behavior: smooth ? 'smooth' : 'auto'
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118 | });
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119 | return true;
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120 | }
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121 | watchScroll(ev) {
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122 | const viewport = this._content.clientHeight,
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123 | ID = this._sections.reduce(
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124 | (carry, el) => {
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125 | const rect = el.getBoundingClientRect(),
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126 | height = rect.bottom - rect.top,
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127 | visible = {
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128 | top: rect.top >= 0 && rect.top < viewport,
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129 | bottom: rect.bottom > 0 && rect.top < viewport
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130 | };
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131 | let pixels = 0;
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132 | if (visible.top && visible.bottom) {
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133 | pixels = height;
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134 | } else if (visible.top) {
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135 | pixels = viewport - rect.top;
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136 | } else if (visible.bottom) {
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137 | pixels = rect.bottom;
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138 | } else if (height > viewport && rect.top < 0) {
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139 | const absolute = Math.abs(rect.top);
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140 | if (absolute < height) pixels = height - absolute;
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141 | }
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142 | pixels = (pixels / height) * 100;
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143 | return pixels > carry[0] ? [pixels, el] : carry;
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144 | },
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145 | [0, null]
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146 | )[1].id;
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147 | this.ID = ID;
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148 | this.scrollMenu(this.ID);
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149 | clearTimeout(this.afterScroll);
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150 | this.afterScroll = setTimeout(
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151 | () => void (this.highlightHeading(this.ID) && this.setHash(this.ID)),
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152 | 100
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153 | );
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154 | }
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155 | }
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156 |
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157 | let constructed = false;
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158 | const construct = () => {
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159 | if (document.readyState !== 'complete' || constructed) return false;
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160 | constructed = true;
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161 |
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162 | if (
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163 | location.pathname.endsWith('index.html') &&
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164 | window.location.protocol === 'https:'
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165 | )
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166 | location.replace('./' + location.hash);
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167 |
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168 | new Scrollnav(
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169 | document.querySelector('aside'),
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170 | document.querySelector('.documentative')
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171 | );
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172 |
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173 | document.querySelector('.toggle button').onclick = () =>
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174 | document.body.classList.toggle('mobilemenu');
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175 |
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176 | if (window.matchMedia) {
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177 | let prev;
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178 | const links = [...document.head.querySelectorAll('link[rel*="icon"]')],
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179 | pointer = document.createElement('link');
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180 | pointer.setAttribute('rel', 'icon');
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181 | document.head.appendChild(pointer);
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182 | setInterval(() => {
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183 | const match = links.find(link => window.matchMedia(link.media).matches);
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184 | if (!match || match.media === prev) return;
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185 | prev = match.media;
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186 | pointer.setAttribute('href', match.getAttribute('href'));
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187 | }, 500);
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188 | links.forEach(link => document.head.removeChild(link));
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189 | }
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190 | };
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191 |
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192 | construct();
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193 | document.addEventListener('readystatechange', construct);
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