taipy/frontend/taipy-gui/src/utils/formatConversion.ts

/*
 * Copyright 2021-2024 Avaiga Private Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */

/*
 * Regular expressions used for parsing sprintf format strings.
 */
const re = {
    text: /^[^\x25]+/, // Matches non-placeholder text
    modulo: /^\x25{2}/, // Matches the '%%' escape sequence
    placeholder: /^\x25?(?:\.(\d+))?([b-giostuvxX])/, // Matches placeholders
};

/*
 * This function formats a precision specifier for a number. It takes an optional precision and specifier string.
 * If no precision is provided, it defaults to 2. The function returns a string that represents the formatted precision.
 */
export const precisionFormat = (precision?: string, specifier?: string): string => {
    // Default to precision of 2 if not specified
    return "." + (precision?.slice(1) ?? "2") + specifier;
};

/*
 * This function parses a sprintf format string and returns an array of strings and objects. Each object has a single
 * key, 'placeholder', that contains the placeholder string.
 */
export const sprintfParse = (fmt?: string): (string | { placeholder: string })[] => {
    let _fmt = fmt;
    let match;
    const parseTree = [];

    while (_fmt) {
        if ((match = re.text.exec(_fmt)) !== null) {
            // Non-placeholder text
            parseTree.push(match[0]);
        } else if ((match = re.modulo.exec(_fmt)) !== null) {
            // '%%' escape sequence
            parseTree.push("%");
        } else if ((match = re.placeholder.exec(_fmt)) !== null) {
            // Placeholder
            if (match && match[0]) {
                parseTree.push({
                    placeholder: match[0],
                });
            }
        } else {
            // If none of the conditions are met, break the loop
            break;
        }

        if (match) {
            _fmt = _fmt.substring(match[0].length);
        }
    }
    return parseTree;
};

/*
 * This function converts a sprintf format string to a D3 format string. It takes an optional sprintf format string and
 * returns a D3 format string. If no format string is provided, it returns an empty string.
 */
export const sprintfToD3Converter = (fmt?: string): string => {
    const sprintfFmtArr = sprintfParse(fmt);
    const objectIndex = sprintfFmtArr.findIndex((element) => typeof element === "object");
    let placeholderValue;

    if (typeof sprintfFmtArr[objectIndex] === "object" && sprintfFmtArr[objectIndex] !== null) {
        placeholderValue = (sprintfFmtArr[objectIndex] as { placeholder: string }).placeholder;
    }

    if (!placeholderValue) {
        return "";
    }

    return placeholderValue.replace(/%([0-9]*)([.][0-9]+)?([bdieufgoxX])/g, (match, width, precision, type) => {
        switch (type) {
            case "b":
            case "d":
            case "e":
            case "o":
            case "x":
            case "X":
                return type;
            case "i":
                return "d";
            case "f":
            case "g":
                return precisionFormat(precision, type);
            case "u":
                return "(";
        }
    });
};

/*
 * This function extracts the prefix from a sprintf format string. It takes an optional sprintf format string and returns
 * a string that represents the prefix of the format string. If no format string is provided, it returns an empty string.
 */
export const extractPrefix = (fmt?: string): string => {
    if (!fmt) return "";
    const sprintfFmtArr = sprintfParse(fmt);
    const objectIndex = sprintfFmtArr.findIndex((element) => typeof element === "object");
    return sprintfFmtArr.slice(0, objectIndex).join("");
};

/*
 * This function extracts the suffix from a sprintf format string. It takes an optional sprintf format string and returns
 * a string that represents the suffix of the format string. If no format string is provided, it returns an empty string.
 */
export const extractSuffix = (fmt?: string): string => {
    if (!fmt) return "";
    const sprintfFmtArr = sprintfParse(fmt);
    const objectIndex = sprintfFmtArr.findIndex((element) => typeof element === "object");
    return sprintfFmtArr.slice(objectIndex + 1).join("");
};