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import _ from 'lodash';
import stringWidth from 'string-width';
const alignments = [
'left',
'right',
'center'
];
/**
* @param {string} subject
* @param {number} width
* @returns {string}
*/
const alignLeft = (subject, width) => {
return subject + ' '.repeat(width);
};
/**
* @param {string} subject
* @param {number} width
* @returns {string}
*/
const alignRight = (subject, width) => {
return ' '.repeat(width) + subject;
};
/**
* @param {string} subject
* @param {number} width
* @returns {string}
*/
const alignCenter = (subject, width) => {
let halfWidth;
halfWidth = width / 2;
if (halfWidth % 2 === 0) {
return ' '.repeat(halfWidth) + subject + ' '.repeat(halfWidth);
} else {
halfWidth = Math.floor(halfWidth);
return ' '.repeat(halfWidth) + subject + ' '.repeat(halfWidth + 1);
}
};
/**
* Pads a string to the left and/or right to position the subject
* text in a desired alignment within a container.
*
* @param {string} subject
* @param {number} containerWidth
* @param {string} alignment One of the valid options (left, right, center).
* @returns {string}
*/
export default (subject, containerWidth, alignment) => {
if (!_.isString(subject)) {
throw new TypeError('Subject parameter value must be a string.');
}
if (!_.isNumber(containerWidth)) {
throw new TypeError('Container width parameter value must be a number.');
}
const subjectWidth = stringWidth(subject);
if (subjectWidth > containerWidth) {
// console.log('subjectWidth', subjectWidth, 'containerWidth', containerWidth, 'subject', subject);
throw new Error('Subject parameter value width cannot be greater than the container width.');
}
if (!_.isString(alignment)) {
throw new TypeError('Alignment parameter value must be a string.');
}
if (!alignments.includes(alignment)) {
throw new Error('Alignment parameter value must be a known alignment parameter value (left, right, center).');
}
if (subjectWidth === 0) {
return ' '.repeat(containerWidth);
}
const availableWidth = containerWidth - subjectWidth;
if (alignment === 'left') {
return alignLeft(subject, availableWidth);
}
if (alignment === 'right') {
return alignRight(subject, availableWidth);
}
return alignCenter(subject, availableWidth);
};
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