refactor all components and isolated from ART dependency

lib/extractText.js

@@ -0,0 +1,96 @@
+import SerializablePath from 'react-native/Libraries/ART/ARTSerializablePath';
+
+const newLine = /\n/g;
+const defaultFontFamily = '"Helvetica Neue", "Helvetica", Arial';
+const fontRegExp = /^\s*((?:(?:normal|bold|italic)\s+)*)(?:(\d+(?:\.\d+)?)[ptexm%]*(?:\s*\/.*?)?\s+)?\s*"?([^"]*)/i;
+const fontFamilyPrefix = /^[\s"']*/;
+const fontFamilySuffix = /[\s"']*$/;
+let cachedFontObjectsFromString = {};
+
+function childrenAsString(children) {
+    if (!children) {
+        return '';
+    }
+    if (typeof children === 'string') {
+        return children;
+    }
+    if (children.length) {
+        return children.join('\n');
+    }
+    return '';
+}
+
+function extractFontAndLines(font, text) {
+    return {
+        font: extractFont(font),
+        lines: text.split(newLine)
+    };
+}
+
+function extractSingleFontFamily(fontFamilyString = defaultFontFamily) {
+    // ART on the web allows for multiple font-families to be specified.
+    // For compatibility, we extract the first font-family, hoping
+    // we'll get a match.
+    return fontFamilyString.split(',')[0]
+        .replace(fontFamilyPrefix, '')
+        .replace(fontFamilySuffix, '');
+}
+
+function parseFontString(font) {
+    if (cachedFontObjectsFromString.hasOwnProperty(font)) {
+        return cachedFontObjectsFromString[font];
+    }
+    let match = fontRegExp.exec(font);
+    if (!match) {
+        return null;
+    }
+    let fontFamily = extractSingleFontFamily(match[3]);
+    let fontSize = +match[2] || 12;
+    let isBold = /bold/.exec(match[1]);
+    let isItalic = /italic/.exec(match[1]);
+    cachedFontObjectsFromString[font] = {
+        fontFamily: fontFamily,
+        fontSize: fontSize,
+        fontWeight: isBold ? 'bold' : 'normal',
+        fontStyle: isItalic ? 'italic' : 'normal'
+    };
+    return cachedFontObjectsFromString[font];
+}
+
+function extractFont(font) {
+    if (font == null) {
+        return null;
+    }
+    if (typeof font === 'string') {
+        return parseFontString(font);
+    }
+    let fontFamily = extractSingleFontFamily(font.fontFamily);
+    let fontSize = +font.fontSize || 12;
+
+    return {
+        fontFamily: fontFamily,
+        fontSize: fontSize,
+        fontWeight: font.fontWeight,
+        fontStyle: font.fontStyle
+    };
+}
+
+const alignments = {
+    right: 1,
+    center: 2,
+    left: 0
+};
+
+export default function(props) {
+    let textPath = props.path ? new SerializablePath(props.path).toJSON() : null;
+    var textFrame = extractFontAndLines(
+        props,
+        childrenAsString(props.children)
+    );
+
+    return {
+        alignment: alignments[props.textAnchor] || 0,
+        frame: textFrame,
+        path: textPath
+    }
+}