R524809
41 lines
2.7 KiB
JavaScript
41 lines
2.7 KiB
JavaScript
import assert from 'node:assert/strict';
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import { calculate } from '../js/tools/stock-return-math.js';
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const base = {price: 220, base_profit_100m: 860, shares_100m: 46.27, exit_pe: 13,
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years: 3, base_year: 2026, target_return: .13, growth_rate: .1,
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safety_margin: 0, annual_dividend_per_share: 0, dividend_growth_rate: 0, annual_dilution_rate: 0};
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const near = (actual, expected, tolerance = 1e-8) => assert.ok(Math.abs(actual - expected) < tolerance, `${actual} ≠ ${expected}`);
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const example = calculate(base);
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near(example.required_growth.required_growth_rate, .0952, .0001);
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near(example.required_growth.required_exit_price, 317.43734);
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near(example.required_growth.required_terminal_profit_100m, 317.43734 * 46.27 / 13);
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// Reverse/forward cash-flow consistency with dividends, dilution, negative rates and FX-normalized inputs.
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for (const patch of [{}, {annual_dividend_per_share: 9.3, dividend_growth_rate: .08},
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{annual_dilution_rate: .02}, {annual_dilution_rate: -.03, growth_rate: -.08},
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{years: 5, target_return: .15}, {target_return: -.15},
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{price: 398 * .85619, annual_dividend_per_share: 5.3 * .85619, base_profit_100m: 2300, shares_100m: 90.93, exit_pe: 15}]) {
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for (const safety_margin of [0, .2, .5]) {
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const input = {...base, ...patch, safety_margin};
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const r = calculate(input);
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const required = r.required_growth_with_safety_margin.required_growth_rate;
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const forward = calculate({...input, growth_rate: required});
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near(forward.max_purchase_price_with_safety_margin, input.price);
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near(forward.margin_of_safety_at_purchase, safety_margin);
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near(r.max_purchase_price_with_safety_margin, r.max_purchase_price_at_target_return * (1 - safety_margin));
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near(calculate({...input, safety_margin: 0}).holding_period_irr, r.holding_period_irr);
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const noMargin = calculate({...input, growth_rate: r.required_growth.required_growth_rate});
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near(noMargin.holding_period_irr, input.target_return);
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}
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}
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const covered = calculate({...base, annual_dividend_per_share: 100, safety_margin: .5});
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assert.equal(covered.required_growth.required_growth_rate, null);
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assert.notEqual(covered.required_growth_with_safety_margin.required_growth_rate, null);
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assert.equal(calculate({...base, annual_dividend_per_share: 500}).required_growth_with_safety_margin.required_growth_rate, null);
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for (const patch of [{price: 0}, {base_profit_100m: -1}, {shares_100m: 0}, {exit_pe: 0},
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{years: 0}, {years: 3.2}, {years: 31}, {target_return: -1}, {annual_dilution_rate: -1},
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{annual_dividend_per_share: -2}, {safety_margin: -1}, {safety_margin: 1}, {price: Infinity}]) {
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assert.throws(() => calculate({...base, ...patch}));
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}
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console.log('✓ 估值示例、现金流反向/正向验证、安全边际、多币种、分红、摊薄及边界条件');
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